Do not require every plugin recorded in the model bundle to be installed when using it

[AdeelH]

Overview

The model bundles record every rastervision plugin that was installed when they were created. Previously, it was required to have all those plugins installed when using those bundles even if not actually needed or otherwise an error would be raised. This has been especially relevant ever since rastervision_gdal_vsi was made optional and not included in the default pip install--meaning users would not have been able to use bundles from the model zoo without installing rastervision_gdal_vsi first.

This PR removes this requirement. Now, the missing plugins are just logged as a warning and no error is raised.

This PR completes a task in #960.

To reproduce:

mamba create rv_1916
mamba activate rv_1916
pip install rastervision

rastervision predict \
https://s3.amazonaws.com/azavea-research-public-data/raster-vision/examples/model-zoo-0.20/isprs-potsdam-ss/model-bundle.zip \
https://s3.amazonaws.com/azavea-research-public-data/raster-vision/examples/model-zoo-0.20/isprs-potsdam-ss/sample-predictions/sample-img-isprs-potsdam-ss.tif \
prediction_output/ \
--channel-order 0 1 2

The above runs into an error complaining about rastervision_gdal_vsi being missing.

Checklist

• Added needs-backport label if PR is bug fix that applies to previous minor release
• Ran scripts/format_code and committed any changes
• Documentation updated if needed
• PR has a name that won't get you publicly shamed for vagueness

Notes

N/A

Testing Instructions

• It should be possible to run the command above without errors.

[codecov]

Codecov Report

Merging #1916 (c922821) into master (32eb656) will decrease coverage by 0.02%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master    #1916      +/-   ##
==========================================
- Coverage   81.57%   81.56%   -0.02%     
==========================================
  Files         190      190              
  Lines        9282     9287       +5     
==========================================
+ Hits         7572     7575       +3     
- Misses       1710     1712       +2     

Files Changed	Coverage Δ
...tervision_pipeline/rastervision/pipeline/config.py	79.61% <66.66%> (+0.01%)	⬆️

... and 1 file with indirect coverage changes