Automatic merge from submit-queue (batch tested with PRs 50103, 49677, 49449, 43586, 48969)

Run kazel on the entire tree

**What this PR does / why we need it**: part of #47558: auto-generate `BUILD` files on the entire tree, since this is what `gazelle` does, and it'll make subsequent reviews easier if less is changing.

**Release note**:

```release-note
NONE
```
/assign
/release-note-none