Add BUILD_BROKEN_USES_NETWORK

Some people apparently still talk to the network during their build.
Allow this temporarily with a BUILD_BROKEN_USES_NETWORK check.

Bug: 129992021
Test: attempt to talk to the network during the build with and without
      this flag.
Change-Id: Ifb967c656aa24c4599e7232d0f1b5a303b5bac52

scripts/build_broken_logs.go

@@ -90,6 +90,10 @@ var buildBrokenSettings = []struct {
 			"Changes.md#LOCAL_MODULE_TAGS",
 		},
 	},
+	{
+		name:     "BUILD_BROKEN_USES_NETWORK",
+		behavior: DefaultDeprecated,
+	},
 }
 
 type ProductBranch struct {