fix: lock invocation per function for not having concurrent requests

[mndeveci]

Which issue(s) does this change fix?

#6157

Why is this change necessary?

When running sam local start-api SAM CLI spins up one container per lambda function. Any concurrent request might fail (or have side-effects) due to this limitation.

How does it address the issue?

Create lock per function endpoint and only allow single execution per function.

What side effects does this change have?

N/A

Mandatory Checklist

PRs will only be reviewed after checklist is complete

• Add input/output type hints to new functions/methods
• Write design document if needed (Do I need to write a design document?)
• Write/update unit tests
• Write/update integration tests
• Write/update functional tests if needed
• make pr passes
• make update-reproducible-reqs if dependencies were changed
• Write documentation

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.