Fixed crashes when user deletes Aggregation field

[Koustubh5585]

Description

Fixed crash when user deletes Aggregation field under Series section and when clicked on red 'X' button

Issues Resolved

#1024

Check List

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[codecov-commenter]

Codecov Report

Merging #1047 (05b70fc) into main (08a8d82) will decrease coverage by 0.01%.
The diff coverage is 33.33%.

@@             Coverage Diff              @@
##               main    #1047      +/-   ##
============================================
- Coverage     54.31%   54.29%   -0.02%     
  Complexity      291      291              
============================================
  Files           277      277              
  Lines          9106     9109       +3     
  Branches       2034     2040       +6     
============================================
  Hits           4946     4946              
- Misses         3990     3993       +3     
  Partials        170      170              

Flag	Coverage Δ
dashboards-observability	48.32% <33.33%> (-0.03%)	⬇️
opensearch-observability	71.87% <ø> (ø)

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

Impacted Files	Coverage Δ
...lity/common/query_manager/ast/tree/aggragations.ts	0.00% <0.00%> (ø)
...ublic/components/visualizations/charts/bar/bar.tsx	12.00% <0.00%> (ø)
...ts/visualizations/charts/financial/gauge/gauge.tsx	29.16% <0.00%> (-0.42%)	⬇️
...ic/components/visualizations/charts/lines/line.tsx	31.63% <50.00%> (-0.33%)	⬇️

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[mengweieric]

LGTM