Allow Installation of Custom Properties Permissions

[shellz-n-stuff]

Description

This PR allows app installations to request tokens with access to the Org level Custom Properties APIs

Refs

1. GitHub App installation access tokens
2. API Docs

[google-cla]

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[shellz-n-stuff]

CLA Signed 🙏

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.87%. Comparing base (2b8c7fa) to head (a4e5e96).
Report is 25 commits behind head on master.

Additional details and impacted files

@@ Coverage Diff @@## master #3108 +/- ##
==========================================
- Coverage 97.72% 92.87% -4.85% 
==========================================
Files 153 170 +17 Lines 13390 11407 -1983 ==========================================
- Hits 13085 10594 -2491 - Misses 215 723 +508 
Partials 90 90 

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[gmlewis]

Thank you, @shellz-n-stuff !
Please run step 4 of CONTRIBUTING.md and push the changes to this PR.

[shellz-n-stuff]

My bad re-lint/generate. All updated 🙏

[gmlewis]

Thank you, @shellz-n-stuff !
LGTM.
Merging.