This is not currently possible. CAM headers are already complex and code is injected into them for various functions; so they should not be edited manually as this is likely to break other functionality and would certainly affect future upgrades of the Cloud Access Manager product.
An enhancement has been raised to look at CAM providing formal support for Google Analytics and not a manual edit of code.
We have raised an enhancement request for product management to consider:
ER#434312: Support for Google Analytics on the App Portal