build(deps): bump boto3 from 1.35.76 to 1.35.81 in /backend

Bumps [boto3](https://github.com/boto/boto3) from 1.35.76 to 1.35.81.
- [Release notes](https://github.com/boto/boto3/releases)
- [Commits](boto/boto3@1.35.76...1.35.81)

---
updated-dependencies:
- dependency-name: boto3
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

Signed-off-by: dependabot[bot] <[email protected]>

backend/requirements.txt

@@ -7,7 +7,7 @@ python-multipart>=0.0.6
 gelf-formatter==0.2.1
 pyyaml>=5.4.1
 user-agents==2.2.0
-boto3==1.35.76
+boto3==1.35.81
 autodynatrace==2.1.1
 PyJWT==2.10.1
 cryptography==44.0.0