remote: flip --incompatible_remote_symlinks

with this flag enabled symlink outputs in remote caching
will be represented as such.

RELNOTES: --incompatible_remote_symlinks has been flipped. The remote caching and execution protocol will now represent symlinks in outputs as such. See #7917 for more details.
PiperOrigin-RevId: 241482756

src/main/java/com/google/devtools/build/lib/remote/options/RemoteOptions.java

@@ -211,7 +211,7 @@ public final class RemoteOptions extends OptionsBase {
 
   @Option(
       name = "incompatible_remote_symlinks",
-      defaultValue = "false",
+      defaultValue = "true",
       category = "remote",
       documentationCategory = OptionDocumentationCategory.EXECUTION_STRATEGY,
       effectTags = {OptionEffectTag.EXECUTION},