fix: Chart crashing if timeseries_limit_metric is an empty array

[kgabryje]

SUMMARY

In some existing charts, timeseries_limit_metric could be an empty array instead of expected string or metric object. That caused a bug where an empty array was pushed to metrics array in buildQuery, causing error like on the screenshot.

Shoutout to @villebro for reproducing the problem and suggesting a solution!

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

[villebro]

LGTM!

[codecov]

Codecov Report

Merging #23480 (0b4b1c5) into master (be2eb31) will increase coverage by 0.00%.
The diff coverage is 100.00%.

❗ Current head 0b4b1c5 differs from pull request most recent head 643b8ef. Consider uploading reports for the commit 643b8ef to get more accurate results

@@           Coverage Diff           @@
##           master   #23480   +/-   ##
=======================================
  Coverage   67.64%   67.64%           
=======================================
  Files        1908     1908           
  Lines       73738    73739    +1     
  Branches     7987     7987           
=======================================
+ Hits        49878    49879    +1     
  Misses      21814    21814           
  Partials     2046     2046           

Flag	Coverage Δ
javascript	53.82% <100.00%> (+<0.01%)	⬆️

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Impacted Files	Coverage Δ
...ontrols/src/operators/utils/extractExtraMetrics.ts	100.00% <100.00%> (ø)

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[sadpandajoe]

🏷️ preset:2023.11