Exempt non-GET requests from the query filter

[fmarier]

Bounce trackers and email newsletter trackers use GET requests (typically redirect chains of them). We can therefore exempt POST requests, which are typically the result of form submissions and a user action. This should help mitigate any webcompat issues arising from filtering parameters that a form might need in order to work properly.

This is also in line with the Mozilla policy on URL decorations.

[stephendonner]

Verified PASSED using

Brave	1.47.39 Chromium: 107.0.5304.91 (Official Build) nightly (x86_64)
Revision	3d5948960d62418160796d5831a4d2d7d6c90fa8-refs/branch-heads/5304@{#1097}
OS	macOS Version 11.7.1 (Build 20G918)

Steps:

1. installed 1.47.39
2. launched Brave
3. loaded https://fmarier.github.io/brave-testing/query-filter.html
4. scrolled down to the POSTS tests section
5. clicked on the button
6. examined the URL bar

Confirmed the URL I ended up on included the ?fbclid=1234 query-string parameter: https://fmarier.org/query-filter/?fbclid=1234

test page	result

[antonok-edm]

AdGuard's removeparam option applies to GET, HEAD, and OPTIONS. I haven't checked the behavior, but uBO's wiki links to the same document for reference. We should do the same.

https://kb.adguard.com/en/general/how-to-create-your-own-ad-filters#removeparam
https://github.com/gorhill/uBlock/wiki/Static-filter-syntax#removeparam

[fmarier]

@antonok-edm HEAD and OPTIONS to be added in #26827.

[Uni-verse]

Verified on Samsung Galaxy S21 using version:

Brave 1.47.167 Chromium: 109.0.5414.80 (Official Build) (64-bit)
Revision 0f69b168d36a06cace4365e9f029fa987afa5633-refs/branch-heads/5414@{https://github.com/brave/brave-browser/issues/1178}
OS Android 12; Build/SP1A.210812.016

1. installed 1.47.x
2. launched Brave
3. loaded https://fmarier.github.io/brave-testing/query-filter.html
4. scrolled down to the POSTS tests section
5. clicked on the button
6. examined the URL bar

Confirmed the URL I ended up on included the ?fbclid=1234 query-string parameter: https://fmarier.org/query-filter/?fbclid=1234

Example	Example