Automated rollback of commit 577cfbc.

*** Reason for rollback ***

Breaking ResultStore customers.

RELNOTES[INC]: --legacy_important_outputs default reverted to true.

*** Original change description ***

Set --legacy_important_outputs to false by default.

This flag reduces the largest proto size, which helps avoid sharp edges with remote execution systems (e.g., #12050).

Closes #14353.

PiperOrigin-RevId: 450067034

src/main/java/com/google/devtools/build/lib/buildeventstream/BuildEventProtocolOptions.java

@@ -23,13 +23,13 @@
 public class BuildEventProtocolOptions extends OptionsBase {
 
   @Option(
-      name = "legacy_important_outputs",
-      defaultValue = "false",
-      documentationCategory = OptionDocumentationCategory.LOGGING,
-      effectTags = {OptionEffectTag.AFFECTS_OUTPUTS},
-      help =
-          "Use this to suppress generation of the legacy important_outputs field in the "
-              + "TargetComplete event.")
+    name = "legacy_important_outputs",
+    defaultValue = "true",
+    documentationCategory = OptionDocumentationCategory.LOGGING,
+    effectTags = {OptionEffectTag.AFFECTS_OUTPUTS},
+    help = "Use this to suppress generation of the legacy important_outputs field in the "
+        + "TargetComplete event."
+  )
   public boolean legacyImportantOutputs;
 
   @Option(