--project-dir flag with relative value appending value twice

Running `pwd` I see `~/projects/french-vocab`. I want to run chalice in `~/projects/french-vocab/api/src`

When running `chalice --project-dir="./api/src" local` or `chalice --project-dir="api/src" local` I get this error message `FileNotFoundError: [Errno 2] No such file or directory: '~/projects/french-vocab/api/src/api/src'`

For all relative values I try I have the same issue where the value I give is repeated twice in the error message output, saying file not found.

The workaround I found is to run `chalice --project-dir="$(pwd)/api/src" local` and use the absolute path. Which works great, but this is an awesome project and figured this is a great chance to contribute an issue!

I'm running this on arch, with the version output as follows. `chalice 1.27.0, python 3.10.7, linux 5.15.69-1-lts`

Start at the chalice --project-dir option handling and reproduce the issue with `chalice --project-dir="api/src" local` from the reported project directory. Trace how the relative value is resolved and verify that the command locates `api/src` once, matching the existing absolute-path behavior.

Written by the indexing model from the issue text.