[No QA] Create Incremental 'withOnyx' migration CI check

.github/scripts/withOnyxMigration.sh

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+#!/bin/bash
+
+RED='\033[0;31m'
+ORANGE='\033[0;33m'
+GREEN='\033[0;32m'
+BOLD_WHITE='\033[1;37m'
+
+# Set IFS to newline to properly handle file names with spaces.
+# This makes 'for' loop treat each line as a separate item.
+IFS=$'\n'
+
+# Fetch the main branch
+git fetch origin main --no-tags --depth=1
+
+# Get the list of modified and added files
+modified_files=$(git diff --name-only --diff-filter=AM origin/main HEAD -- '*.tsx')
+
+# Count instances of 'withOnyx' on main branch and current branch
+count_main=0
+count_current=0
+
+echo -e "\nWe're gradually moving from 'withOnyx' to 'useOnyx'. 'useOnyx' hook simplifies the code, offers performance benefits and improves TypeScript compilation time."
+echo -e "For more details, see https://expensify.slack.com/archives/C01GTK53T8Q/p1725905735105989.\n"
+echo -e "${BOLD_WHITE}If this check is blocking you on something that is very urgent, you can always ignore it.\n"
+
+if [ -z "$modified_files" ]; then
+  echo -e "${GREEN}No changes detected. Exiting."
+  exit 0
+fi
+
+for file in $modified_files; do
+  # 2>/dev/null is used to ignore errors when the file doesn't exist in the main branch
+  count_main_file=$(git show origin/main:"$file" 2>/dev/null | grep -o 'withOnyx<' | wc -l)
+  count_current_file=$(grep -o 'withOnyx<' "$file" | wc -l)
+
+  count_main=$((count_main + count_main_file))
+  count_current=$((count_current + count_current_file))
+
+  if ((count_current_file > 0 && count_current_file >= count_main_file)); then
+    echo -e "${ORANGE}WARNING: '$file' was modified on this branch and still contains 'withOnyx' usages. Consider replacing it with 'useOnyx' hooks."
+  fi
+done
+
+if ((count_current == 0 && count_main == 0)); then
+  echo -e "${GREEN}No changes detected. Exiting."
+  exit 0
+fi
+
+if ((count_current == count_main)); then
+  echo -e "${RED}\nERROR: There's no reduction of 'withOnyx' usages on the current branch compared to main. Please migrate one of the above files to use 'useOnyx' hooks instead."
+  exit 1
+fi
+
+if ((count_current > count_main)); then
+  echo -e "${RED}\nERROR: There's an increase in 'withOnyx' usages on the current branch compared to main. Please migrate it to use 'useOnyx' hooks instead."
+  exit 1
+fi
+
+echo -e "${GREEN}\nIn the modified files, the usage of 'withOnyx' has been reduced from $count_main to $count_current. Great job!"

.github/workflows/withOnyxMigration.yml

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+name: Incremental 'withOnyx' migration
+
+on:
+  workflow_call:
+  pull_request:
+    types: [opened, synchronize]
+    branches-ignore: [staging, production]
+    paths: ['**.ts']
+
+jobs:
+  withOnyxMigration:
+    if: ${{ github.actor != 'OSBotify' || github.event_name == 'workflow_call' }}
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: ./.github/actions/composite/setupNode
+
+      - name: Check for 'withOnyx' usages in modified files
+        run: ./.github/scripts/withOnyxMigration.sh