Issues with the sentry-native submodule

### Description

Sometimes when creating a fresh clone of the repository, trying to fetch/pull from the remote fails with:
```
Fetching submodule modules/Ben.Demystifier
Fetching submodule modules/perfview
Fetching submodule modules/sentry-native
Fetching submodule modules/sentry-native/external/benchmark
fatal: cannot chdir to '../../../../../../../modules/sentry-native/external/benchmark': No such file or directory
Fetching submodule modules/sentry-native/external/breakpad
fatal: cannot chdir to '../../../../../../../modules/sentry-native/external/breakpad': No such file or directory
Fetching submodule modules/sentry-native/external/crashpad
fatal: cannot chdir to '../../../../../../../modules/sentry-native/external/crashpad': No such file or directory
Fetching submodule modules/sentry-native/external/libunwindstack-ndk
fatal: cannot chdir to '../../../../../../../modules/sentry-native/external/libunwindstack-ndk': No such file or directory
Fetching submodule modules/sentry-native/external/third_party/lss
fatal: cannot chdir to '../../../../../../../../modules/sentry-native/external/third_party/lss': No such file or directory
Errors during submodule fetch:
external/benchmark
external/breakpad
external/crashpad
external/libunwindstack-ndk
external/third_party/lss
Errors during submodule fetch:
modules/sentry-native
```

This may be related to an issue I bumped into some time ago... ultimately it's missing a commit in `mini_chromium`. It can be resolved manually be removing the remote that's configured for that submodule presently and adding `git@github.com:getsentry/mini_chromium.git` instead (since the commit that's checked out for that submodule only exists on our fork - not on the upstream origin).

We should try to address this permanently. I still haven't figured out a way to reliably reproduce the issue - although I'm bumping into it much more frequently since switching to using [git worktrees](https://git-scm.com/docs/git-worktree) for my workflow.