Editor preferences ignoring scope precedence

[colin-grant-work]

Bug Description:

Editor preferences are ignoring the precedence of preference scopes and accepting the most recent change to preference values.

Steps to Reproduce:

1. Open a workspace and open a text file in that workspace.
2. In that workspace, set e.g. editor.fontSize to some non-default value.
3. Observe that the new setting takes effect in your open file.
4. In user scope, set the same preference to some other non-default value.
5. Observe that that new setting also takes effect in your open file, even though it should be ignored because it is overridden by the workspace value.

Additional Information

• Operating System: MacOS, Electron
• Theia Version: 5f887e2