Firestore: Set DEFAULT_RELATIVE_INDEX_READ_COST_PER_DOCUMENT to 8 in query_engine.ts

[dconeybe]

In query_engine.ts the DEFAULT_RELATIVE_INDEX_READ_COST_PER_DOCUMENT value was hardcoded as 2, which was just copied from the Android SDK. Some experimentation has been done and we found that this value should not be hardcoded universally, but should be adjusted based on the browser/OS on which the code is running. More experiment data is needed, so changing the hardcoded value to 8 is the lowest-common-denominator of the experiment data captured so far. A later PR will refine this value.

[changeset-bot]

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Latest commit: 246dc0a

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[google-oss-bot]

Size Report ¹

Affected Products

No changes between base commit (fbd8e0e) and merge commit (a99b82b).

Test Logs

• Base (fbd8e0e): https://github.com/firebase/firebase-js-sdk/actions/runs/6089156651
• Merge (a99b82b): https://github.com/firebase/firebase-js-sdk/actions/runs/6100275035

1. https://storage.googleapis.com/firebase-sdk-metric-reports/RFvaF70udX.html

[google-oss-bot]

Size Analysis Report ¹

Affected Products

No changes between base commit (fbd8e0e) and merge commit (a99b82b).

Test Logs

• Base (fbd8e0e): https://github.com/firebase/firebase-js-sdk/actions/runs/6089156651
• Merge (a99b82b): https://github.com/firebase/firebase-js-sdk/actions/runs/6100275035

1. https://storage.googleapis.com/firebase-sdk-metric-reports/Gh0M6Pnhvp.html