Fixes for Language Server sync server

[somebody1234]

Pull Request Description

• Closes New IDE Backend Crash Opening Project #8398

Important Notes

• The original error caused by a failing text/openFile (openTextFile) is still present, but (seemingly?) harder to repro now

Checklist

Please ensure that the following checklist has been satisfied before submitting the PR:

• The documentation has been updated, if necessary.
• Screenshots/screencasts have been attached, if there are any visual changes. For interactive or animated visual changes, a screencast is preferred.
• All code follows the
  Scala,
  Java,
  and
  Rust
  style guides. In case you are using a language not listed above, follow the Rust style guide.
• All code has been tested:
  • Unit tests have been written where possible.
  • If GUI codebase was changed, the GUI was tested when built using ./run ide build.

[Frizi]

This was the FileReadResult type, but improperly named. According to docs it does have a nested contents field. So it was probably allright, bar the incorrect name.

https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#result-5

[somebody1234]

actually i discovered this was incorrect, when i was implementing this:

enso/app/gui2/ydoc-server/languageServerSession.ts

Lines 585 to 596 in 2d2c9c9

	case LsSyncState.Synchronized: {
	this.withState(LsSyncState.Reloading, async () => {
	const promise = Promise.all([
	this.ls.readFile(this.path),
	this.ls.fileChecksum(this.path),
	])
	this.setLastAction(promise)
	const [contents, checksum] = await promise
	this.syncFileContents(contents.contents, checksum.checksum)
	})
	return
	}

on that note... i'm not 100% sure about this. it doesn't affect the fix if it's removed - it's entirely possible that I've misunderstood what reload is supposed to do

[somebody1234]

note that there is a FileContents type: https://github.com/enso-org/enso/blob/develop/docs/language-server/protocol-language-server.md#filecontents

also note that *Result types were basically only added so that the Result interfaces are valid TS code - in GUI2 these should correspond to response.*