Revert "Merge branch 'prozlach/bump_proxy_buffers' into 'main'"

What does this merge request do and why?

This reverts merge request Bump proxy buffers size to accomodate content-s... (!3632 - merged) as it's no longer required once Revert "Merge branch 'ga4-csp-google-signal' in... (gitlab!147740 - merged) is merged.

Impacted categories

The following categories relate to this merge request:

• gdk-reliability - e.g. When a GDK action fails to complete.
• gdk-usability - e.g. Improvements or suggestions around how the GDK functions.
• gdk-performance - e.g. When a GDK action is slow or times out.

Merge request checklist

• This change is backward compatible. If not, please include steps to communicate to our users.
• Tests added for new functionality. If not, please raise an issue to follow-up.
• Documentation added/updated, if needed.
• Announcement added, if change is notable.
• gdk doctor test added, if needed.
• Add the ~highlight label if this MR should be included in the CHANGELOG.md.