Catch error for invalid URI.

[JPBergsma]

This is a second attempt to resolve issue #2197 and should enable connecting to a MongoDB Atlas Cluster via its connection string.

[codecov]

Codecov Report

Attention: Patch coverage is 50.00000% with 3 lines in your changes missing coverage. Please review.

Project coverage is 90.66%. Comparing base (7798f67) to head (196a827).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
optimade/server/config.py	50.00%	3 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2201      +/-   ##
==========================================
- Coverage   90.69%   90.66%   -0.04%     
==========================================
  Files          75       75              
  Lines        4858     4861       +3     
==========================================
+ Hits         4406     4407       +1     
- Misses        452      454       +2     

Flag	Coverage Δ
project	90.66% <50.00%> (-0.04%)	⬇️
validator	90.66% <50.00%> (-0.04%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.