fix: onSave datasource raises React error

[mistercrunch]

CATEGORY

Choose one

• Bug Fix
• Enhancement (new features, refinement)
• Refactor
• Add tests
• Build / Development Environment
• Documentation

SUMMARY

When saving a datasource in the explore view, React throws up

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TEST PLAN

Wrote a unit test to make sure React doesn't fail when props are null

[codecov-io]

Codecov Report

Merging #8049 into master will increase coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #8049      +/-   ##
==========================================
+ Coverage   65.56%   65.56%   +<.01%     
==========================================
  Files         469      469              
  Lines       22480    22482       +2     
  Branches     2442     2444       +2     
==========================================
+ Hits        14739    14741       +2     
  Misses       7621     7621              
  Partials      120      120

Impacted Files	Coverage Δ
...src/explore/components/controls/MetricsControl.jsx	80.13% <100%> (+0.26%)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ed8bb1b...055eaa9. Read the comment docs.