fix(.github): add --force option to vcs import

[youtalk]

Description

This PR adds the –force option because there are cases where the import fails when executing the vcs import of autoware-nightly.repos.

$ vcs import --help
usage: vcs import [-h] [--input FILE_OR_URL] [--force] [--shallow] [--recursive] [--retry N] [--skip-existing] [--debug] [-w N] [--repos] [path]

Import the list of repositories

optional arguments:
-h, --help show this help message and exit

"import" command parameters:
--input FILE_OR_URL Where to read YAML from (default: -)
--force Delete existing directories if they don't contain the repository being imported (default: False)
--shallow Create a shallow clone without a history (default: False)
--recursive Recurse into submodules (default: False)
--retry N Retry commands requiring network access N times on failure (default: 2)
--skip-existing Don't overwrite existing directories or change custom checkouts in repos using the same URL (but fetch repos with same URL) (default: False)

Common parameters:
--debug Show debug messages (default: False)
-w N, --workers N Number of parallel worker threads (default: 11)
--repos List repositories which the command operates on (default: False)
path Base path to clone repositories to (default: .)

Tests performed

Not applicable.

Effects on system behavior

Not applicable.

Interface changes

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