[Desktop] Do not proxy downloads for widevine

[jumde]

Test plan

See brave/brave-core#5846

Description

Downloads for widevine should not be proxied, it should directly reach out to *.gvt1.com and *.dl.google.com domains.

[LaurenWags]

Verified passed with

Brave | 1.10.93 Chromium: 83.0.4103.106 (Official Build) (64-bit)
-- | --
Revision | ce7134bb3d95141cd18f1e65772a4247f282d950-refs/branch-heads/4103@{#694}
OS | macOS Version 10.14.6 (Build 18G3020)

• Verified test plan from Fix 10269: Do not proxy downloads for Widevine brave-core#5846 using clean profile
• Confirmed able to play videos on Netflix and bitmovin after Widevine was downloaded

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Verification PASSED on Win 10 x64 using the following build:

Brave | 1.10.93 Chromium: 83.0.4103.106 (Official Build) (64-bit)
--- | ---
Revision | ce7134bb3d95141cd18f1e65772a4247f282d950-refs/branch-heads/4103@{#694}
OS | Windows 10 OS Version 2004 (Build 19041.329)
JavaScript | V8 8.3.110.13

• Verified test plan from Fix 10269: Do not proxy downloads for Widevine brave-core#5846 using clean profile
• Confirmed able to play videos on Netflix and bitmovin after Widevine was downloaded

---

Verified on Linux by @kjozwiak:

Brave	1.10.93 Chromium: 83.0.4103.106 (Official Build) (64-bit)
Revision	ce7134bb3d95141cd18f1e65772a4247f282d950-refs/branch-heads/4103@{#694}
OS	Linux