CI - Set Unity testsuite timeout to 30m (#3015)

# Description of Changes

Just what it says on the can. This test suite can sometimes mysteriously
hang for a long time, so a timeout will help kill this (and free up
resources) earlier.

# API and ABI breaking changes

None

# Expected complexity level and risk

1

# Testing

None really. I guess I could test this by adding a step that just sleeps
forever, but this is basically just setting some data.

Co-authored-by: Zeke Foppa <bfops@users.noreply.github.com>

Author: bfops

.github/workflows/csharp-test.yml

@@ -13,6 +13,7 @@ jobs:
     concurrency:
       group: unity-test-${{ github.event.pull_request.number || github.ref }}
       cancel-in-progress: true
+    timeout-minutes: 30
     steps:
       - name: Checkout repository
         uses: actions/checkout@v4