fix(android): fix build on AGP 9 / RN 0.87

[wperkins-micron]

I am currently updating an Android app from React Native 0.77.3 to 0.87.1. I followed the upgrade helper, which also bumps the Gradle version from 8.10.x to 9.4.1. Attempting to build and run the app under AGP 9 causes the build to fail with the following error:

error Failed to install the app. Command failed with exit code 1: ./gradlew app:installDebug -PreactNativeDevServerPort=8081 FAILURE: Build failed with an exception. * What went wrong:
A problem occurred configuring project ':react-native-pdf'.
> defaultConfig contains custom BuildConfig fields, but the feature is disabled. To enable the feature, add the following to your module-level build.gradle: `android.buildFeatures.buildConfig = true`

This is fixed by adding the following block of code inside the android block in android/build.gradle:

buildFeatures {
        buildConfig = true
}

See also a similar issue and open pull request for another RN community module:

• Build fails with AGP 9: defaultConfig contains custom BuildConfig fields, but the feature is disabled react-native-checkbox/react-native-checkbox#257
• react-native-checkbox/react-native-checkbox@2794ece
• Text copy-pasted from my similar pull request here: fix(android): add buildConfig = true, to fix build error on AGP 9 react-native-datetimepicker/datetimepicker#1065

No AI was used in the creation of this patch or pull request in any way.