Commit only tracked files in tracked filter view

[parthokunda]

• PR Description
  When in tracked filter view, selecting a folder for staging should only stage files that are tracked by git. Previously, it staged even untracked files that were not in view.
  All staged (even untracked) files are shown in tracked filter view.
  Fixes When hiding untracked files, adding a folder adds also untracked files (git add instead of git add -u) #4245

• Please check if the PR fulfills these requirements

• Cheatsheets are up-to-date (run go generate ./...)
• Code has been formatted (see here)
• Tests have been added/updated (see here for the integration test guide)
• Text is internationalised (see here)
• If a new UserConfig entry was added, make sure it can be hot-reloaded (see here)
• Docs have been updated if necessary
• You've read through your own file changes for silly mistakes etc

[parthokunda]

All staged (even untracked) files are shown in tracked filter view. I have not written any test for this part. Do you think I should write one?