Fix browser specific manifest generation

[MakMuftic]

Fixes: #12532

Explanation:
I tracked a bug inside Metamasks code that creates browser-specific manifests. The idea here is to have _base.json manifest that holds manifest properties that are needed on all browsers and then also have browser-specific manifests such as chrome.json. Then, when manifest for specific browser distribution is created, these two manifests are merged into one. The problem occurs when you have array property such as permissions in both _base.json and chrome.json (browser-specific manifest). Below you can find examples of how this merge worked before, and how it works now.

OLD BEHAVIOUR

  /* _base.json */
  "permissions": [
    "storage",
    "unlimitedStorage",
    "clipboardWrite",
    "http://localhost:8545/",
    "https://*.infura.io/",
    "activeTab",
    "webRequest",
    "*://*.eth/",
    "notifications"
  ]
  
  /* chrome.json */
  "permissions": [
    "chrome-extension://*/*"
  ]
  
  /* results in merged permissions as shown below */
  /* problem is that new permissions from browser specific manifest ovveride base permission /*
  "permissions": [
    "chrome-extension://*/*",  /* notice that storage permission is missing */
    "unlimitedStorage",
    "clipboardWrite",
    "http://localhost:8545/",
    "https://*.infura.io/",
    "activeTab",
    "webRequest",
    "*://*.eth/",
    "notifications"
  ]
  

NEW BEHAVIOUR

  /* _base.json */
  "permissions": [
    "storage",
    "unlimitedStorage",
    "clipboardWrite",
    "http://localhost:8545/",
    "https://*.infura.io/",
    "activeTab",
    "webRequest",
    "*://*.eth/",
    "notifications"
  ]
  
  /* chrome.json */
  "permissions": [
    "chrome-extension://*/*"
  ]
  
  /* results in merged permissions as shown below */
  "permissions": [ 
    "storage"
    "unlimitedStorage",
    "clipboardWrite",
    "http://localhost:8545/",
    "https://*.infura.io/",
    "activeTab",
    "webRequest",
    "*://*.eth/",
    "notifications",
    "chrome-extension://*/*"
  ]
  

I have read the CLA Document and I hereby sign the CLA

[github-actions]

CLA Signature Action: All authors have signed the CLA. You may need to manually re-run the blocking PR check if it doesn't pass in a few minutes.

[MakMuftic]

I have read the CLA Document and I hereby sign the CLA

[Gudahtt]

LGTM, great catch!

[Gudahtt]

Hey @MakMuftic, could you update this branch to resolve conflicts? Thanks!

[kumavis]

couldnt modify this pr so i resolved the conflict here #13007

[darkwing]

Superceded by #13007