ci: reduce number of groups for 0.34 e2e runs (#6968)

.github/workflows/e2e-nightly-34x.yml

@@ -17,7 +17,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        group: ['00', '01', '02', '03']
+        group: ['00', '01']
     runs-on: ubuntu-latest
     timeout-minutes: 60
     steps:
@@ -37,7 +37,7 @@ jobs:
       - name: Generate testnets
         working-directory: test/e2e
         # When changing -g, also change the matrix groups above
-        run: ./build/generator -g 4 -d networks/nightly
+        run: ./build/generator -g 2 -d networks/nightly
 
       - name: Run testnets in group ${{ matrix.group }}
         working-directory: test/e2e