ci: bump MSan fuzz timeout

The MSan fuzz job has little headroom on fork CI when caches miss.

Examples from Sjors/bitcoin:

- PR 116 timed out after 2h30m: https://github.com/Sjors/bitcoin/actions/runs/27465468297/job/81187008305?pr=116

- PR 117 passed in 2h24m47s: https://github.com/Sjors/bitcoin/actions/runs/27465461797/job/81186956747?pr=117

- PR 118 passed in 2h18m22s: https://github.com/Sjors/bitcoin/actions/runs/27465761345/job/81187860567?pr=118

Bump the timeout to 180 minutes to leave room for runner variance.

.github/workflows/ci.yml

@@ -534,7 +534,7 @@ jobs:
           - name: 'MSan, fuzz'
             warp-runner: 'warp-ubuntu-latest-x64-8x'
             fallback-runner: 'ubuntu-latest'
-            timeout-minutes: 150
+            timeout-minutes: 180
             file-env: './ci/test/00_setup_env_native_fuzz_with_msan.sh'
 
           - name: 'MSan'