feat: exclude idle time in user engagement duration

[zhu-xiaowei]

Description

1. exclude idle time in user engagement duration
2. use throttling to optimize mouse move and scroll performance

General Checklist

• [x] Added new tests to cover change, if needed
• [ ] Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• [x] Documentation update for the change if required
• [x] PR title conforms to conventional commit style
• [ ] If breaking change, documentation/changelog update with migration instructions

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (3f23ec3) to head (0dce34f).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #52 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 25 25 Lines 1140 1173 +33 Branches 226 215 -11 ========================================= + Hits 1140 1173 +33 ```

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