Update commit filtering and diff view for file-level permissions to better reflect P4 behavior
Created by: mollylogue
This PR makes two main changes:
- Updates sub-repo filtering when listing commits to return a commit which modifies any file the user has access to (previously the user had have access to all files modified in the commit to view the commit)
- Updates the handling of git diffs to ensure that only the files which the user has access to in the commit/range of commits are shown.
Outstanding questions:
- Do we need to do filtering for DiffSymbols ?
Test plan
- Existing/updated/added unit tests all pass
- Local testing w/ github.com/mollylogue/testing repo using the
path_excludes
rule**_test.go
demonstrates expected behavior for listing commits and viewing diffs