Fix remote extension syncing (#42918)

Closes #40906
Closes #39729

SFTP uploads weren't quoting the install directory which was causing
extension syncing to fail. We were also only running `install_extension`
once per remote-connection instead of once per project (thx @feeiyu for
pointing this out) so extension weren't being loaded in subsequently
opened remote projects.

Release Notes:

- N/A

---------

Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>

crates/remote/src/transport/ssh.rs

@@ -304,7 +304,7 @@ impl RemoteConnection for SshRemoteConnection {
                 let mut child = sftp_command.spawn()?;
                 if let Some(mut stdin) = child.stdin.take() {
                     use futures::AsyncWriteExt;
-                    let sftp_batch = format!("put -r {src_path_display} {dest_path_str}\n");
+                    let sftp_batch = format!("put -r \"{src_path_display}\" \"{dest_path_str}\"\n");
                     stdin.write_all(sftp_batch.as_bytes()).await?;
                     stdin.flush().await?;
                 }