Allow deeplinking to timeline page based on frame number

As of https://github.com/flutter/flutter/pull/82934 , both the engine and framework now share a canonical frame number. We'd like to use this as a key to allow deeplinks from the CLI or IDEs into the timeline for the purpose of surfacing slow frame events in the tool.

For more context see: https://docs.google.com/document/d/1wSDNcG0ww2V6JX1EE8avilCwnOiRVy83zSCWt916O0o/edit?resourcekey=0-S4WRTBTn9b4fMLt7gnpgjA