GHA/windows: increase timeout for vcpkg jobs due to slowness

The openssl job no longer fits into 10 minutes since the 20241015.1.0
GHA windows-latest image update. This caused all runs to fail.

The `run tests` step takes ~10 minutes now, up from ~4. This is
6 minutes more than before these updates. It's seen with other vcpkg
jobs too, tests run slower than half speed since.

Bump the timeout to make it, though the headroom is now less than it
was.

Before:
https://github.com/curl/curl/actions/runs/11386748199/job/31679733295
https://github.com/curl/curl/actions/runs/11347976608/job/31560690219

After:
https://github.com/curl/curl/actions/runs/11462332743/job/31893491625?pr=15364

Ref: fcc4cdb1d0
Ref: https://github.com/curl/curl/pull/15335#issuecomment-2423759953
Follow-up to 1e0305973c #15356
Closes #15364

.github/workflows/windows.yml

@@ -792,7 +792,7 @@ jobs:
 
       - name: 'cmake run tests'
         if: ${{ matrix.tflags != 'skipall' && matrix.tflags != 'skiprun' }}
-        timeout-minutes: 10
+        timeout-minutes: 12
         run: |
           export TFLAGS='-j8 ~WebSockets ~SCP ~612 ${{ matrix.tflags }}'
           TFLAGS+=' ~987'  # 'SMTPS with redundant explicit SSL request'