Add cleaner dubious ownership error

[Kapparina]

• PR Description
  Resolves An error occurred! -- Detected dubious ownership in repository #3303, resolves "failed: fatal: detected dubious ownership in repository" when running lazygit on a newly initialized repository on a external drive #3757

Whilst the above issues expect lazygit to prompt the user to prompt whether it should modify their global Git configuration, I believe it is more pertinent that the user instead inform themselves of what's actually going on.

This PR adds a new known error message covering "dubious ownership". Rather than panicking when Git throws such an error, the below error message will be displayed:

Git detected unsafe/dubious ownership of the repository's root directory

Whilst there is a solution/workaround, please understand the relevant risks and purpose of this warning!

See 'git/git@8959555' for background information on said risks

This error is unrelated to lazygit
For more information, see 'https://git-scm.com/docs/git-config/2.35.2#Documentation/git-config.txt-safedirectory'

Whilst I'm not against contributing to the implementation of the expected behaviour in the aforementioned issues, I think informing users of the risks involved is a necessary starting point.

• 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