Correctly handle network issues during LSP server installation (#9460)

Closes https://github.com/zed-industries/zed/issues/9458

When flying in a plane being totally offline, I've discovered that my
Rust projects do not have any LSP support and rust-analyzer disappeared
out of `~/Library/Application Support/Zed/languages/rust-analyzer/`
directory.

Looking at the
[bad.log](https://github.com/zed-industries/zed/files/14627508/bad.log),
it appears that `get_language_server_command` tries to find a newer LSP
server version and fails on
https://github.com/zed-industries/zed/blob/80bc6c8cc800e23ba79723b0c46b731a62203224/crates/language/src/language.rs#L339

bailing out of all installation related-methods up to here:


https://github.com/zed-industries/zed/blob/80bc6c8cc800e23ba79723b0c46b731a62203224/crates/project/src/project.rs#L2916

where the code thinks that the binary installation process had failed,
cleans the existing directory and tries to install the language server
again:

```log
[2024-03-17T15:14:13+02:00 WARN  isahc::handler] request completed with error: failed to resolve host name
[2024-03-17T15:14:13+02:00 ERROR project] failed to start language server "rust-analyzer": error fetching latest release
[2024-03-17T15:14:13+02:00 ERROR project] server stderr: Some("")
[2024-03-17T15:14:13+02:00 INFO  project] retrying installation of language server "rust-analyzer" in 1s
[2024-03-17T15:14:13+02:00 ERROR util] crates/lsp/src/lsp.rs:720: oneshot canceled
[2024-03-17T15:14:14+02:00 INFO  project] About to spawn test binary
[2024-03-17T15:14:14+02:00 WARN  project] test binary failed to launch
[2024-03-17T15:14:14+02:00 WARN  project] test binary check failed
[2024-03-17T15:14:14+02:00 INFO  project] beginning to reinstall server
[2024-03-17T15:14:14+02:00 INFO  language::language_registry] deleting server container
[2024-03-17T15:14:14+02:00 INFO  language::language_registry] starting language server "rust-analyzer", path: "/Users/someonetoignore/work/other/local_test", id: 2
[2024-03-17T15:14:14+02:00 INFO  language] fetching latest version of language server "rust-analyzer"
[2024-03-17T15:14:14+02:00 WARN  isahc::handler] request completed with error: failed to resolve host name
[2024-03-17T15:14:14+02:00 ERROR project] failed to start language server "rust-analyzer": error fetching latest release
[2024-03-17T15:14:14+02:00 ERROR project] server stderr: Some("")
[2024-03-17T15:14:14+02:00 INFO  project] retrying installation of language server "rust-analyzer" in 1s
[2024-03-17T15:14:15+02:00 ERROR util] crates/languages/src/rust.rs:335: no cached binary
[2024-03-17T15:14:15+02:00 INFO  project] About to spawn test binary
............
```

The PR extracts away all binary fetching-related code into a single
method that does not fail the entire `get_language_server_command` and
allows it to recover and reuse the existing binary:


[good.log](https://github.com/zed-industries/zed/files/14627507/good.log)

```log
[2024-03-17T15:12:24+02:00 INFO  language::language_registry] starting language server "rust-analyzer", path: "/Users/someonetoignore/work/other/local_test", id: 1
[2024-03-17T15:12:24+02:00 INFO  language] fetching latest version of language server "rust-analyzer"
[2024-03-17T15:12:24+02:00 WARN  isahc::handler] request completed with error: failed to resolve host name
[2024-03-17T15:12:24+02:00 INFO  language] failed to fetch newest version of language server LanguageServerName("rust-analyzer"). falling back to using "/Users/someonetoignore/Library/Application Support/Zed/languages/rust-analyzer/rust-analyzer-2024-03-11"
[2024-03-17T15:12:24+02:00 INFO  lsp] starting language server. binary path: "/Users/someonetoignore/Library/Application Support/Zed/languages/rust-analyzer/rust-analyzer-2024-03-11", working directory: "/Users/someonetoignore/work/other/local_test", args: []
```

Release Notes:

- Fixed language servers erased from the disk when project is opened
offline

crates/languages/src/rust.rs

@@ -1,4 +1,4 @@
-use anyhow::{anyhow, bail, Result};
+use anyhow::{anyhow, bail, Context, Result};
 use async_compression::futures::bufread::GzipDecoder;
 use async_trait::async_trait;
 use futures::{io::BufReader, StreamExt};
@@ -79,7 +79,7 @@ impl LspAdapter for RustLspAdapter {
             .assets
             .iter()
             .find(|asset| asset.name == asset_name)
-            .ok_or_else(|| anyhow!("no asset found matching {:?}", asset_name))?;
+            .with_context(|| format!("no asset found matching `{asset_name:?}`"))?;
         Ok(Box::new(GitHubLspBinaryVersion {
             name: release.tag_name,
             url: asset.browser_download_url.clone(),