Allow formatting when ScriptAnalysis is off

[TylerLeonhardt]

fixes PowerShell/vscode-powershell#2543

With ScriptAnalysis turned off...

"powershell.scriptAnalysis.enable": false,

this disables PSScriptAnalyzer capabilities in the extension including:

• "Problems" in your open editor file
• Formatting

Since that was off, formatting wasn't working for users (and would throw a weird null ref due to returning null instead of Task.FromResult(null)).

With that said, I don't see why this needs to be the case. You should be able to run the formatter and have "Problems" turned off. This PR pushes the ScriptAnalysis enabled test up a layer while allowing the Formatting path to trigger the creation of the AnalysisEngine.

[rjmholt]

Suggested change

	if (_analysisEngineLazy == null ||
	(_pssaSettingsFilePath != null
	&& !File.Exists(_pssaSettingsFilePath)))
	if (_analysisEngineLazy == null
	|| (_pssaSettingsFilePath != null
	&& !File.Exists(_pssaSettingsFilePath)))

[TylerLeonhardt]

Here is an overview of what got changed by this pull request:

Complexity increasing per file
==============================
- src/PowerShellEditorServices/Services/Analysis/PssaCmdletAnalysisEngine.cs  1
         

See the complete overview on Codacy

[TylerLeonhardt]

just gonna give the person in the issue a chance to get back to me on if this fixed their issue.