geometry relation support for data search

[ischneider]

• optional arg in filter creation
• add support in CLI filter command
• remove some superfluous respx.mock annotations

I considered adding this for the other CLI commands but this would have required significant reworking how geometry is handled, as we currently pass it along as a top-level item in the request and relation is only supported in a filter.

While it would be conceivable to unpack a user's filters and merge in a geometry filter, this felt beyond the scope of the issue.

In other words, with this MR, the only way to use relation via the CLI is to use planet data filter --geom=... --geom-relation=within | planet data search psscene --filter=-

Related Issue(s):

Closes #1204

Proposed Changes:

For inclusion in changelog (if applicable):

1. Add relation support for geometry filter in data

PR Checklist:

• [X] This PR is as small and focused as possible
• [X] If this PR includes proposed changes for inclusion in the changelog, the title of this PR summarizes those changes and is ready for inclusion in the Changelog.
• [X] I have updated docstrings for function changes and docs in the 'docs' folder for user interface / behavior changes
• [X] This PR does not break any examples or I have updated them