fix: conditionally assign logFilePaths only when value is not undefined

[Copilot]

OperationExecutionRecord unconditionally overwrote this.logFilePaths with undefined when createLogFile is false, discarding any previously set value (e.g. from cache restoration in CacheableOperationPlugin).

Changes

• OperationExecutionRecord.ts: Guard the assignment so this.logFilePaths is only updated when logFilePaths !== undefined:

// Before
this.logFilePaths = logFilePaths; // always set, even when undefined

// After
if (logFilePaths !== undefined) {
  this.logFilePaths = logFilePaths;
}

• Change file: Patch bump for @microsoft/rush.