Increase timeout of Devtools tests (#159759)

Increases from the default 30 minutes to 45.
After devtools testing was re-enabled in
https://github.com/flutter/tests/pull/432 the tree is red because the
test shard exceeds 30 minutes again.

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.ci.yaml

@@ -566,6 +566,7 @@ targets:
       shard: customer_testing
       tags: >
         ["framework", "hostonly", "shard", "linux"]
+      test_timeout_secs: "2700" # Allows 45 minutes (up from 30 default)
 
   - name: Linux docs_publish
     recipe: flutter/docs
@@ -3796,6 +3797,7 @@ targets:
       shard: customer_testing
       tags: >
         ["framework", "hostonly", "shard", "mac"]
+      test_timeout_secs: "2700" # Allows 45 minutes (up from 30 default)
 
   - name: Mac dart_plugin_registry_test
     recipe: devicelab/devicelab_drone
@@ -5538,6 +5540,7 @@ targets:
       shard: customer_testing
       tags: >
         ["framework", "hostonly", "shard", "windows"]
+      test_timeout_secs: "2700" # Allows 45 minutes (up from 30 default)
 
   - name: Windows framework_tests_libraries
     recipe: flutter/flutter_drone