Fix strict deps violation

```
src/main/java/com/google/devtools/build/lib/analysis/starlark/StarlarkRuleClassFunctions.java:990: error: [strict] Using type com.google.devtools.build.lib.cmdline.LabelValidator from an indirect dependency (TOOL_INFO: "//src/main/java/com/google/devtools/build/lib/cmdline:LabelValidator"). See command below **
      LabelValidator.parseAbsoluteLabel(labelString);
      ^
```

src/main/java/com/google/devtools/build/lib/analysis/BUILD

@@ -387,6 +387,7 @@ java_library(
         "//src/main/java/com/google/devtools/build/lib/buildeventstream/proto:build_event_stream_java_proto",
         "//src/main/java/com/google/devtools/build/lib/causes",
         "//src/main/java/com/google/devtools/build/lib/cmdline",
+        "//src/main/java/com/google/devtools/build/lib/cmdline:LabelValidator",
         "//src/main/java/com/google/devtools/build/lib/collect",
         "//src/main/java/com/google/devtools/build/lib/collect/compacthashset",
         "//src/main/java/com/google/devtools/build/lib/collect/nestedset",