Bump starlette from 0.38.6 to 0.40.0 in /api/tests

Bumps [starlette](https://github.com/encode/starlette) from 0.38.6 to 0.40.0.
- [Release notes](https://github.com/encode/starlette/releases)
- [Changelog](https://github.com/encode/starlette/blob/master/docs/release-notes.md)
- [Commits](encode/starlette@0.38.6...0.40.0)

---
updated-dependencies:
- dependency-name: starlette
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <support@github.com>

api/tests/requirements.txt

@@ -522,9 +522,9 @@ sniffio==1.3.1 \
     # via
     #   anyio
     #   httpx
-starlette==0.38.6 \
-    --hash=sha256:4517a1409e2e73ee4951214ba012052b9e16f60e90d73cfb06192c19203bbb05 \
-    --hash=sha256:863a1588f5574e70a821dadefb41e4881ea451a47a3cd1b4df359d4ffefe5ead
+starlette==0.40.0 \
+    --hash=sha256:1a3139688fb298ce5e2d661d37046a66ad996ce94be4d4983be019a23a04ea35 \
+    --hash=sha256:c494a22fae73805376ea6bf88439783ecfba9aac88a43911b48c653437e784c4
     # via fastapi
 typer==0.12.5 \
     --hash=sha256:62fe4e471711b147e3365034133904df3e235698399bc4de2b36c8579298d52b \