linux: Show warning if file picker portal is missing (#14401)

This PR adds a warning when the file chooser couldn't be opened on Linux

It's quite confusing when trying to open a file and apparently nothing
happens:

fixes https://github.com/zed-industries/zed/issues/11089,
https://github.com/zed-industries/zed/issues/14328,
https://github.com/zed-industries/zed/issues/13753#issuecomment-2225812703,
https://github.com/zed-industries/zed/issues/13766,
https://github.com/zed-industries/zed/issues/14384,
https://github.com/zed-industries/zed/issues/14353,
https://github.com/zed-industries/zed/issues/9209


![image](https://github.com/user-attachments/assets/5acabdaa-7a9d-4225-9480-e371d20387c3)


Release Notes:

- N/A

Cargo.lock

@@ -341,8 +341,9 @@ dependencies = [
 
 [[package]]
 name = "ashpd"
-version = "0.9.0"
-source = "git+https://github.com/bilelmoussaoui/ashpd?rev=29f2e1a#29f2e1a6f4b0911f504658f5f4630c02e01b13f2"
+version = "0.9.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "bfe7e0dd0ac5a401dc116ed9f9119cf9decc625600474cb41f0fc0a0050abc9a"
 dependencies = [
  "async-fs 2.1.1",
  "async-net 2.0.0",