Ensure all pre-installed extensions doesn't have Chrome webstore link

[srirambv]

Description

Ensure all pre-installed extensions doesn't have Chrome webstore link

Steps to Reproduce

1. Build from source (aa02380)
2. Go to chrome://extensions
3. Click details on PDFJS extension which is bundled into browser
4. Has link to Chrome webstore

Actual result:

Expected result:

Should not contain Chrome web store link. Either remove or replace with brave extension link

Reproduces how often:

100%

Brave version (about:brave info)

aa02380

Additional Information

#212

[srirambv]

Verification Passed on:

Brave	0.55.6 Chromium: 70.0.3538.16 (Official Build) dev (64-bit)
Revision	16ed95b41bb05e565b11fb66ac33c660b721f778-refs/branch-heads/3538@{#306}
OS	Linux

Verification PASSED on:

Brave	0.55.6 Chromium: 70.0.3538.16 (Official Build) dev (64-bit)
Revision	16ed95b41bb05e565b11fb66ac33c660b721f778-refs/branch-heads/3538@{#306}
OS	Windows

Went through verification using the following build under macOS 10.13.6 x64 - PASSED

Brave	0.55.10 Chromium: 70.0.3538.22 (Official Build) beta(64-bit)
Revision	ac9418ba9c3bd7f6baaffa0b055dfe147e0f8364-refs/branch-heads/3538@{#468}
OS	Mac OS X