Investigate whether caching git config is worth it

[jesseduffield]

From @stefanhaller

The fact that we cache git configs is annoying for testing. I typed git config status.showUntrackedFiles false while lazygit was running, and was confused that it didn't make a difference, until I remembered that we cache git configs. I ran into this before in other cases, and I do wonder if the slight performance gain that we get from caching is worth it compared to this confusion.

We should investigate the performance impact of not caching, and if there's only a marginal difference, we should stop caching git config values, as it's annoying for users who want to change those configs mid-session, and it makes the code more complicated.

[jesseduffield]

This is the file that currently does the caching so we could just make it not cache anything and then measure how much overhead it adds to each git action: https://github.com/jesseduffield/lazygit/blob/show-files-filter-status/pkg/commands/git_config/cached_git_config.go

[stefanhaller]

It just occurred to me that a good middle ground might be to keep caching the values, but to drop the cache whenever we get the focus, so that users can change a config in a different terminal and it takes effect immediately when they return to lazygit.

PR: #4376

[stefanhaller]

Addressed by #4376; closing.