User's Custom Keybinding Should Always Take Precedence

**Is your feature request related to a problem? Please describe.**
Yes, v0.41.0 overrode some of my custom keybindings causing what had been working for months to suddenly fail.

**Describe the solution you'd like**
A user's existing custom keybindings should always take precedence over new default keybindings introduced.

An easy win would at least be to have the [Keybindings](https://github.com/jesseduffield/lazygit?tab=readme-ov-file#keybindings) section of the README point users to the [default config's keybindings](https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md#default) so users can identify what new is causing the breakage / conflict.

**Additional context**
See [Bug 3461](https://github.com/jesseduffield/lazygit/issues/3461) caused by [commit 8ca78412](https://github.com/jesseduffield/lazygit/commit/8ca78412acdc73526248ff10c332f98ceba39fd2) which could have been avoided by such an enhancement. Introducing potential breakages such as this should be accompanied with documentation in the README or release notes to enable a user to identify the conflict and find a work around.