Bump starlette from 0.50.0 to 1.3.1 (#1311)

Summary:

Bump `starlette` from 0.50.0 to 1.3.1 and `fastapi` from 0.128.0 to 0.137.1
in `uv.lock`. The starlette upgrade requires unlocking fastapi since fastapi
0.128.0 pins starlette <0.51.

Recreated from D108447803 (bot diff lacking Phab CI bundle, originally targeted 1.0.1;
resolved to 1.3.1 which is the current latest).

Reviewed By: seemethere

Differential Revision: D108650949

Author: kiukchung