Tie the query filter to Shields status

[fmarier]

As suggested in #4239 (comment) and #4239 (comment), we could tie the query filter to whether or not Shields are enabled on the destination URL.

This would enable web developers to test their trackers without needing another browser, and it would make it possible to add more generic-looking query parameters (e.g. #8975).

[stephendonner]

Verified FIXED using beta and the testplan in brave/brave-core#7968 with

Brave	1.22.49 Chromium: 89.0.4389.72 (Official Build) beta (x86_64)
Revision	3f345f156bfd157bd1bea06310e55f3fb2490359-refs/branch-heads/4389@{#1393}
OS	macOS Version 11.2.2 (Build 20D80)

1. Open https://brave.com/?fbclid=1234 in a new tab.
2. Check that the fbclid query parameter is missing from the URL bar.

3. Turn Shields OFF for brave.com.
4. Open https://brave.com/?fbclid=5678 in a new tab.
5. Check that the fbclid query parameter is present in the URL bar.

6. Turn Shields ON for brave.com.
7. Open https://brave.com/?__s=abcd in a new tab.
8. Check that the __s query parameter is missing from the URL bar.

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Verification passed on

Brave	1.22.53 Chromium: 89.0.4389.72 (Official Build) beta (64-bit)
Revision	3f345f156bfd157bd1bea06310e55f3fb2490359-refs/branch-heads/4389@{#1393}
OS	Ubuntu 18.04 LTS

Verified test plan from brave/brave-core#7968

Shields on, https://brave.com/?fbclid=1234

Shields off, https://brave.com/?fbclid=5678

Shields on, https://brave.com/?__s=abcd

---

Verification passed on

Brave | 1.22.56 Chromium: 89.0.4389.72 (Official Build) dev (64-bit)
-- | --
Revision | 3f345f156bfd157bd1bea06310e55f3fb2490359-refs/branch-heads/4389@{#1393}
OS | Windows 10 OS Version 2004 (Build 19041.804)

Verified test plan from brave/brave-core#7968

Shields on, https://brave.com/?fbclid=1234

Shields off, https://brave.com/?fbclid=1234

Shields on, https://brave.com/?__s=abcd

[srirambv]

Verification passed on OnePlus 6T with Android 10 running 1.22.54 x64 beta build

• Verified test plan from Tie query filter to Shields setting and add Drip tracker brave-core#7968

Android.ARM.mp4

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Verification passed on Samsung Tab A with Android 10 running 1.22.54 x64 beta build

• Verified test plan from Tie query filter to Shields setting and add Drip tracker brave-core#7968

Android.Tab.mp4