[Manual Backport 2.x] Add support for register data sources during the absence of local cluster

[RyanL1997]

Description

Add support for register data sources during the absence of local cluster

Issues Resolved

• Resolve the 500 errors when there is no backend plugins to consume the requests

Check List

• New functionality includes testing.
  • All tests pass, including unit test, integration test and doctest
• New functionality has been documented.
  • New functionality has javadoc added
  • New functionality has user manual doc added
• Commits are signed per the DCO using --signoff

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 56.48%. Comparing base (fc85856) to head (0f8bf37).
Report is 21 commits behind head on 2.x.

Additional details and impacted files

@@            Coverage Diff             @@
##              2.x    #2144      +/-   ##
==========================================
- Coverage   57.01%   56.48%   -0.53%     
==========================================
  Files         379      390      +11     
  Lines       14541    14975     +434     
  Branches     3898     4066     +168     
==========================================
+ Hits         8290     8459     +169     
- Misses       6183     6454     +271     
+ Partials       68       62       -6     

Flag	Coverage Δ
dashboards-observability	56.48% <ø> (-0.53%)	⬇️

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