fix: prevent native histogram double-rebuild race condition

[nicwestvold]

✨ Description

Native histogram metrics could fail to load: subscribeToStateChanges set panelConfig.type = 'heatmap' but omitted metricType: 'native-histogram', so queries never updated. A secondary race allowed both detection paths to independently trigger buildVizPanel().

📖 Changes

• Set metricType: 'native-histogram' in the subscribeToStateChanges path
• Fix stale closure: read this.state.panelConfig at resolution time
• Skip state update if the other path already applied heatmap type
• Unsubscribe on first Done event unconditionally
• Replace ! assertions in query builders with guards that warn and skip

🧪 How to test?

• Open a native histogram metric; verify it renders as a heatmap with native histogram queries
• Automated: new unit tests in GmdVizPanel.test.ts and the three query builder test files

[Copilot]

Pull request overview

This PR addresses a race in GmdVizPanel where two async detection paths (metadata vs. returned dataframe type) could both trigger a rebuild when a metric is a native histogram, and adds defensive handling in query builders so persisted configs referencing unknown PromQL functions don’t crash query construction.

Changes:

• Add guards in GmdVizPanel to prevent redundant “switch-to-heatmap” rebuilds and unsubscribe deterministically on first LoadingState.Done.
• Add runtime checks around PROMQL_FUNCTIONS.get(fn) in timeseries/stat/percentiles query param builders, logging and skipping unknown functions.
• Add/extend unit tests for the histogram race guard paths and unknown-function handling.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
src/shared/GmdVizPanel/GmdVizPanel.tsx	Adds guards + earlier unsubscribe to prevent double-rebuild when native histogram is detected via two async paths.
src/shared/GmdVizPanel/tests/GmdVizPanel.test.ts	New tests covering the two-path guard behavior and unsubscribe behavior.
src/shared/GmdVizPanel/types/timeseries/getTimeseriesQueryRunnerParams.ts	Skips unknown PromQL function entries and logs a warning instead of crashing.
src/shared/GmdVizPanel/types/timeseries/tests/getTimeseriesQueryRunnerParams.test.ts	Adds test asserting unknown PromQL functions are skipped and warning is logged.
src/shared/GmdVizPanel/types/stat/getStatQueryRunnerParams.ts	Same unknown-function guard + warning for stat query builder.
src/shared/GmdVizPanel/types/stat/tests/getStatQueryRunnerParams.test.ts	Adds unknown-function test coverage for stat query builder.
src/shared/GmdVizPanel/types/percentiles/getPercentilesQueryRunnerParams.ts	Adds unknown-function guards for both histogram and non-histogram percentile query paths.
src/shared/GmdVizPanel/types/percentiles/tests/getPercentilesQueryRunnerParams.test.ts	Adds tests for unknown-function handling in both percentile query paths.

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