[toggleAutoSave]: Toggle Auto save doesn't go back to the selected mode (fix: #211538)

[MohamedLamineAllal]

Solve issue: #211538

• Did use the StorageService to save the value. And use it from there.
• By introducing the StorageService, i had to update the TestStorageService constructs in 2 other tests files

For Tests

No tests were implemented for the whole toggle functionality (my changes, and the changes before).

• I wanted to implement a unit test for it. But i couldn't figure out how to execute a command giving the context in https://github.com/MohamedLamineAllal/vscode/blob/f3d3c69532d74b0dc267dcb9670c98eb0b516915/src/vs/workbench/contrib/files/test/browser/editorAutoSave.test.ts#L102
• If you can point me to how i should go about it. I will add the tests.

Otherwise, i did test the changes of this PR. And it does fix well the problem. Also all tests are passing.