Revert "feat: add firefox for ui_tests (#3459)" (#3868)

This reverts commit c3445b102f.

.github/workflows/snapshot_release.yml

@@ -13,7 +13,7 @@ jobs:
 
     strategy:
       matrix:
-          browser: ['edge', 'chrome', 'firefox']
+          browser: ['edge', 'chrome']
 
     steps:
     - uses: actions/checkout@v2.3.4
@@ -68,11 +68,6 @@ jobs:
           npm i -g yarn
           yarn install
 
-    - name: Disable multi-process on firefox
-      if: matrix.browser == 'firefox'
-      run: |
-        export MOZ_FORCE_DISABLE_E10S=1
-
     - name: Lint with ES-Lint & Prettier
       run: |
           cd ./main/tests/cypress