fix: time grain can't be removed in explore

[zhaoyongjie]

SUMMARY

There is a long-term issue in the Time Grain control that it can't be cleared time grain value even though remove it or select Original value.

This PR intends to fix it.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

Before

time.grain.-.before.mov

After

time.grain.after.mov

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 #21644 (6f9edc8) into master (9dd102f) will not change coverage.
The diff coverage is 25.00%.

@@           Coverage Diff           @@
##           master   #21644   +/-   ##
=======================================
  Coverage   66.83%   66.83%           
=======================================
  Files        1798     1798           
  Lines       68823    68823           
  Branches     7333     7333           
=======================================
  Hits        45996    45996           
+ Misses      20949    20948    -1     
- Partials     1878     1879    +1     

Flag	Coverage Δ
javascript	53.16% <25.00%> (ø)

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

Impacted Files	Coverage Δ
...et-ui-chart-controls/src/shared-controls/index.tsx	54.23% <25.00%> (-2.91%)	⬇️
...ugins/plugin-chart-echarts/src/Gauge/buildQuery.ts	66.66% <0.00%> (-8.34%)	⬇️
...s/plugin-chart-handlebars/src/plugin/buildQuery.ts	100.00% <0.00%> (ø)
...ontend/src/explore/controlUtils/getControlState.ts	90.16% <0.00%> (+4.91%)	⬆️

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[villebro]

Thanks for fixing this annoying but pretty major bug - minor nit, LGTM

[villebro]

Is there some reason we're not just doing state.form_data?.time_grain_sqla || 'P1D' here?

[zhaoyongjie]

When Time Grain control be set to "Original value" or just removal, the time_grain_sqla in the form_data will be null. If time_grain_sqla get a null value, the 'P1D' will always be set to control, in this case, the chart will never use an empty time grain value.
For instance:

1. make a Line Chart and set Original value to Time Grain, and then save it; next, go to chart list; then, reopen the chart.
2. if use state.form_data?.time_grain_sqla || 'P1D' the Time Grain will return P1D