ci: revert unnecessary sharp installation (#659)

Author: KazuCocoa

.github/workflows/functional-test.yml

@@ -88,8 +88,6 @@ jobs:
     - run: npm install -g appium
     - run: |
         appium plugin install images
-        # for macOS env specific
-        npm install -g --os=darwin --cpu=arm64 sharp
         appium plugin install execute-driver
         # Workaround to keep symlink to global appium
         appium driver install xcuitest
@@ -167,8 +165,6 @@ jobs:
         npm install -g mjpeg-consumer
     - run: |
         appium plugin install images
-        # for macOS env specific
-        npm install -g --os=darwin --cpu=arm64 sharp
         appium plugin install execute-driver
         # Workaround to keep symlink to global appium
         appium driver install xcuitest