Make CI upload xcactivitylog and improve metrics script flexibility

[Copilot]

Fix

Refactored CI build metrics collection to be more flexible and self-contained:

• Parameterized paths: track-apple-metrics.sh now accepts xcresult and DerivedData paths as mandatory inputs (script fails if not provided)
• Self-managed artifact uploads: Script uses buildkite-agent artifact upload directly instead of relying on artifact_paths enumeration in pipeline.yml
• Immediate uploads: Each file is uploaded immediately after generation, ensuring artifacts are tracked even if subsequent steps fail

# Before: hardcoded paths
xcrun xcresulttool get build-results --path build/results/Simplenote.xcresult ...
xclogparser dump --derived_data ./DerivedData ...

# After: required path arguments (fails if not provided)
XCRESULT_PATH="${1:?Error: xcresult path required as first argument}"
DERIVED_DATA_PATH="${2:?Error: DerivedData path required as second argument}"
xcrun xcresulttool get build-results --path "$XCRESULT_PATH" ...
xclogparser dump --derived_data "$DERIVED_DATA_PATH" ...

Test

1. Push to trigger CI
2. Verify build/xcresulttool/*.json and build/xclogparser-reports/*.json appear in Buildkite artifacts
3. Verify xclogparser and xcresulttool commands complete successfully in logs
4. Verify script fails with clear error if paths are not provided

Review

Standard CI change review. One developer sufficient.

Release

These changes do not require release notes.

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[mokagio]

@copilot do not use a default if paths not found. Fail the script instead.

Also, upload files as soon as generated, not at the end, so if something fails along the way, the files that had been generated before will be tracked anyway.

[Copilot]

@copilot do not use a default if paths not found. Fail the script instead.

Also, upload files as soon as generated, not at the end, so if something fails along the way, the files that had been genera...

Done in 7990804. Changed to use ${1:?Error: ...} syntax to require paths and fail if not provided. Each file is now uploaded immediately after generation using individual buildkite-agent artifact upload calls.