[ci]: Add workflow to guard against growing bundle size (jaegertracing#2586)

## Which problem is this PR solving?
- fixes jaegertracing#2581 

## Description of the changes
This GH Workflow would go through the following steps:

1. Calculate the actual bundle size by using `build` directory generated
when we run `npm run build`
2. Save that size to a `new_bundle_size.txt` file
3. Now fetch the `bundle_size.txt` file from cache, if present.
4. If cache hits, compare the `bundle_size.txt` (contains old size) with
the `new_bundle_size.txt` (contains new size).
5. If its more than 2%, fail the CI
6. Else pass it.
7. If cache miss, save the `bundle_size.txt` to cache
8. Finally, if everything's alright, save the current bundle size file
to cache. (but only on pushes to main branch)

## How was this change tested?
- Example run:
https://github.com/hari45678/jaeger-ui/actions/runs/12724047648/job/35469797958#step:8:27

## Checklist
- [x] I have read
https://github.com/jaegertracing/jaeger/blob/master/CONTRIBUTING_GUIDELINES.md
- [x] I have signed all commits
- [x] I have added unit tests for the new functionality
- [x] I have run lint and test steps successfully
  - for `jaeger`: `make lint test`
  - for `jaeger-ui`: `npm run lint` and `npm run test`

---------

Signed-off-by: Hariom Gupta <[email protected]>

Author: hari45678

Diff for: .github/workflows/check_bundle.yml

@@ -0,0 +1,69 @@
+name: Bundle Size Check
+on:
+  pull_request:
+    branches: [main]
+    
+  push:
+    branches: [main]
+
+concurrency:
+  group: ${{ github.workflow }}-${{ (github.event.pull_request && github.event.pull_request.number) || github.ref || github.run_id }}
+  cancel-in-progress: true
+
+jobs:
+  build-and-check:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4.2.1
+      - name: Setup Node.js
+        uses: actions/setup-node@39370e3970a6d050c480ffad4ff0ed4d3fdee5af # v4.1.0
+        with:
+          node-version-file: '.nvmrc'
+          cache: 'npm'
+          
+      - name: Install dependencies
+        run: npm ci
+        
+      - name: Build
+        run: npm run build
+        
+      - name: Calculate bundle size
+        run: |
+          TOTAL_SIZE=$(du -sb packages/jaeger-ui/build | cut -f1)
+          echo "$TOTAL_SIZE" > new_bundle_size.txt
+          echo "Total bundle size: $TOTAL_SIZE bytes"
+          
+      - name: Restore previous bundle size
+        id: cache-bundle-size
+        uses: actions/cache/restore@v4
+        with:
+          path: bundle_size.txt
+          key: jaeger-ui-bundle-size
+          
+      - name: Compare bundle sizes
+        if: steps.cache-bundle-size.outputs.cache-hit == 'true'
+        run: |
+          OLD_BUNDLE_SIZE=$(cat bundle_size.txt)
+          NEW_BUNDLE_SIZE=$(cat new_bundle_size.txt)
+          echo "Previous bundle size: $OLD_BUNDLE_SIZE bytes"
+          echo "New bundle size: $NEW_BUNDLE_SIZE bytes"
+          
+          SIZE_CHANGE=$(( $NEW_BUNDLE_SIZE - $OLD_BUNDLE_SIZE ))
+          PERCENTAGE_CHANGE=$(( SIZE_CHANGE * 100 / $OLD_BUNDLE_SIZE ))
+          echo "Size change: $PERCENTAGE_CHANGE%"
+          if [ $PERCENTAGE_CHANGE -gt 2 ]; then
+            echo "❌ Bundle size increased by more than 2% ($PERCENTAGE_CHANGE%)"
+            exit 1
+          else
+            echo "✅ Bundle size change is within acceptable range ($PERCENTAGE_CHANGE%)"
+          fi
+          
+      - name: Update bundle size file
+        run: mv new_bundle_size.txt bundle_size.txt
+        
+      - name: Save new bundle size
+        if: github.event_name == 'push' && github.ref == 'refs/heads/main'
+        uses: actions/cache/save@v4
+        with:
+          path: bundle_size.txt
+          key: jaeger-ui-bundle-size