Formatter moves comments between f-string expr and format spec to invalid location

### Summary

It looks like this case snuck though the latest f-string changes. [playground](https://play.ruff.rs/03a16098-8ac1-490e-8378-863c302d1126) this code is valid
```py
f"{1
#test
:}"
```
But gets made invalid by the formatter
```py
f"{
    1:
    # test
}"
```
(Or in the case of a multiline string, has behavior change)

### Version

ruff 0.12.0 (87f0feb21 2025-06-17) + playground