Fix adblocking regression for requests made by Service Workers

[kdzwinel]

Description

Resource that should be blocked, according to the custom filters, doesn't get blocked when requested by a service worker.

Steps to Reproduce

1. Go to brave://adblock/
2. Add ||bad.third-party.site^ to the 'Custom Filters' textarea
3. Go to https://privacy-test-pages.glitch.me/privacy-protections/request-blocking/
4. Click "start the test" button

Actual result:

"serviceworker-fetch" test is green meaning that request to https://bad.third-party.site/privacy-protections/request-blocking/block-me/fetch.json?serviceworker-… has been successfully made. This can be additionally verified using DevTools:

Expected result:

All tests should be gray meaning that all requests to bad.third-party.site failed to load.

Brave version (brave://version info)

Brave | 1.19.86 Chromium: 88.0.4324.96 (Official Build) (x86_64)
Revision | 68dba2d8a0b149a1d3afac56fa74648032bcf46b-refs/branch-heads/4324@{#1784}
OS | macOS Version 11.1 (Build 20C69)

Miscellaneous Information:

I haven't verified if this issue only affects custom filters or if it's a more general gap that also affects the default protections.

[antonok-edm]

Thanks for the report @kdzwinel and good find. I verified that this also affects the default protections; will work on getting a fix in soon.

[LaurenWags]

Verified using

Brave	1.21.64 Chromium: 88.0.4324.182 (Official Build) beta (x86_64)
Revision	73ee5087001dcef33047c4ed650471b225dd8caf-refs/branch-heads/4324@{#2202}
OS	macOS Version 10.15.7 (Build 19H512)

Verified test plan from brave/brave-core#7910

Custom Filters	Default Filters

---

Verification passed on

Brave	1.21.64 Chromium: 88.0.4324.182 (Official Build) beta (64-bit)
Revision	73ee5087001dcef33047c4ed650471b225dd8caf-refs/branch-heads/4324@{#2202}
OS	Ubuntu 18.04 LTS

Verified test plan from brave/brave-core#7910

---

Verification passed on

Brave | 1.21.68 Chromium: 89.0.4389.58 (Official Build) (64-bit)
-- | --
Revision | 1a139f28ecc27719439e37c6b1533cee999cb802-refs/branch-heads/4389@{#1134}
OS | Windows 10 OS Version 2004 (Build 19041.804)

Verified test plan from brave/brave-core#7910