ci: Bump vl-convert-python to 1.7.0

[dangotbanned]

Related

• fix(typing): Add patch for vl-convert-python=1.7.0
• feat: Adds vl_convert.pyi type stub vl-convert#185
• python: Expose vendored vega version string vl-convert#191
• feat: Generate expr method signatures, docs #3600 (comment)

I ran into this on another branch, good news is the new stubs are working correctly:

(doc) PS C:\Users\danie\Documents\GitHub\altair> mypy tools
tools\generate_schema_wrapper.py:496: error: Argument 1 to "_vega_lite_props_only" has incompatible type
"dict[Literal['carbong10', 'carbong100', 'carbong90', 'carbonwhite', 'dark', 'excel', 'fivethirtyeight', 'ggplot2', 'googlecharts', 'latimes', 'powerbi', 'quartz', 'urbaninstitute', 'vox'], dict[str, Any]]"; expected
"dict[str, dict[str, Any]]"  [arg-type]
        themes = dict(_vega_lite_props_only(vlc.get_themes(), vl_props))