Stop setting `-no-module-directories` in ExoPlayer javadoc generation

This flag was introduced to fix links in javadoc search when generating
it with Java 11: <unknown commit>

The flag is no longer supported with Java 17 (which is required for
Gradle 8.0+), and seems to no longer be needed: I generated the javadoc
with it removed and the search links work OK.

PiperOrigin-RevId: 536738686

javadoc_combined.gradle

@@ -35,7 +35,6 @@ class CombinedJavadocPlugin implements Plugin<Project> {
             links "https://developer.android.com/reference", guavaReferenceUrl
             encoding = "UTF-8"
           }
-          options.addBooleanOption "-no-module-directories", true
           exclude "**/BuildConfig.java"
           exclude "**/R.java"
           doFirst {

javadoc_library.gradle

@@ -31,7 +31,6 @@ android.libraryVariants.all { variant ->
                   "https://guava.dev/releases/$project.ext.guavaVersion/api/docs"
             encoding = "UTF-8"
         }
-        options.addBooleanOption "-no-module-directories", true
         exclude "**/BuildConfig.java"
         exclude "**/R.java"
         doFirst {