chore: removing unused chartMetadata field

[rusackas]

SUMMARY

In auditing plugin framework code, it seems the chartMetadata field show is not being used anywhere. Let's trim the fat!

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

Merging #25926 (72b869f) into master (2bd6119) will decrease coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #25926      +/-   ##
==========================================
- Coverage   69.04%   69.02%   -0.02%     
==========================================
  Files        1938     1938              
  Lines       75842    75840       -2     
  Branches     8426     8425       -1     
==========================================
- Hits        52363    52349      -14     
- Misses      21309    21321      +12     
  Partials     2170     2170              

Flag	Coverage Δ
hive	53.65% <ø> (ø)
mysql	?
postgres	78.31% <ø> (-0.02%)	⬇️
presto	53.60% <ø> (ø)
python	82.83% <ø> (-0.04%)	⬇️
sqlite	76.97% <ø> (ø)
unit	55.59% <ø> (ø)

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

Files	Coverage Δ
...superset-ui-core/src/chart/models/ChartMetadata.ts	100.00% <ø> (ø)

... and 6 files with indirect coverage changes

📣 Codecov offers a browser extension for seamless coverage viewing on GitHub. Try it in Chrome or Firefox today!

[michael-s-molina]

LGTM