PHOENIX-7937 Trim whitespace in EXPLAIN FORMAT JSON scan attributes

[apurtell]

Trim scan attribute string values before populating ExplainPlanAttributes. Text plan is unchanged. The JSON field values are canonicalized.

Co-authored-by: Claude Opus 4.8[1m] noreply@anthropic.com

[Copilot]

Pull request overview

This PR canonicalizes (trims) whitespace in scan-related string fields when populating ExplainPlanAttributes for EXPLAIN FORMAT JSON, while keeping the human-readable/text explain output unchanged.

Changes:

• Trim explainScanType before storing it in ExplainPlanAttributes.
• Trim keyRanges before storing it in ExplainPlanAttributes.
• Update/adjust JSON-baseline expectations in ExplainPlanTest to match the canonicalized output.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 2 comments.

File	Description
phoenix-core/src/test/java/org/apache/phoenix/query/explain/ExplainPlanTest.java	Updates expected JSON attributes to match trimmed/canonical scan attribute strings; trims inputs in helper used to build expected scan JSON.
phoenix-core-client/src/main/java/org/apache/phoenix/iterate/ExplainTable.java	Trims scan attribute string values (explainScanType, keyRanges) when populating ExplainPlanAttributes for JSON output.

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[apurtell]

This one is annoying because it had a much larger silly impact on tests than expected, and sometimes you just have to grab the IDE and do it by hand. I think I have a handle on it now.