Get rid of third party dependency to GoogleChrome/web-vitals

[ekremney]

Is your feature request related to a problem? Please describe.
Yes, the current dependency on the third-party library GoogleChrome/web-vitals for CWV collection introduces an unnecessary external dependency.

Describe the solution you'd like
Move the CWV collection logic from GoogleChrome/web-vitals to an inlined rum-enhancer. The data collection logic for CWV metrics will remain unchanged, ensuring consistency.

Additional context
The solution provided should ensure that CWV metrics like TTFB, FCP, LCP, CLS, and INP are collected consistently using the Performance API. However, note that CWV data collection is not possible on iOS devices due to limited support of the Performance API in Safari