FIX: JsonParser / ParseStringValue now creates unescaped strings

[AlexTyrer]

Description

Comparing escaped and non-escaped strings is very slow - this happens when devices are deactivated/reactivated such as when the Quest2 headset and controllers enter and awake from sleep mode.

The high cost comes from having to compare each string character-by-character (skipping '' escapes) each time entering the C# runtime to perform System.Globalization.ToUpperInvariant.

Changes made

This change to TryMatchDisconnectedDevice() means that any parsed strings that contain escape characters are converted to non-escaped strings for much quicker comparison.

This saves approximately 0.5ms / frame when an Oculus headset or controller is reactivated.

Testing

Local testing with the Quest2 headset and controllers using Superluminal to capture the cost of device awakening.

Risk

We allocate a temporary string where before we did not.

Checklist

Before review:

• [ ] Changelog entry added.
  • Explains the change in Changed, Fixed, Added sections.
  • For API change contains an example snippet and/or migration example.
  • JIRA ticket linked, example (case %<ID>%). If it is a private issue, just add the case ID without a link.
  • Jira port for the next release set as "Resolved".
• [ ] Tests added/changed, if applicable.
  • Functional tests Area_CanDoX, Area_CanDoX_EvenIfYIsTheCase, Area_WhenIDoX_AndYHappens_ThisIsTheResult.
  • Performance tests.
  • Integration tests.
• [ ] Docs for new/changed API's.
  • Xmldoc cross references are set correctly.
  • Added explanation how the API works.
  • Usage code examples added.
  • The manual is updated, if needed.

During merge:

• [ ] Commit message for squash-merge is prefixed with one of the list:
  • NEW: ___.
  • FIX: ___.
  • DOCS: ___.
  • CHANGE: ___.
  • RELEASE: 1.1.0-preview.3.

After merge:

• [ ] Create forward/backward port if needed. If you are blocked from creating a forward port now please add a task to ISX-1444.