include DISALLOW_TASK_EXECUTION in build scans

to make it easier to determine whether the scan was suppose to be mostly up-to-date

Bug: 237440163
Test: Run `./gradlew -Pandroidx.verifyUpToDate :help --scan` and see that there are two scans and each lists a value for androidx.disallowTaskExecution
Test: Trehugger runs busytown/*.sh

Change-Id: Ia26838c80b8d6250f9b2be7d0c2db34adc6b9b42
diff --git a/settings.gradle b/settings.gradle
index 60f1d67..8334a54 100644
--- a/settings.gradle
+++ b/settings.gradle
@@ -91,6 +91,7 @@
         value("androidx.compose.multiplatformEnabled", isMultiplatformEnabled().toString())
         value("androidx.projects", getRequestedProjectSubsetName() ?: "Unset")
         value("androidx.useMaxDepVersions", providers.gradleProperty("androidx.useMaxDepVersions").isPresent().toString())
+        value("androidx.disallowTaskExecution", providers.environmentVariable("DISALLOW_TASK_EXECUTION").isPresent().toString())
 
         publishAlways()
         publishIfAuthenticated()