Move TopicScreen strings to resources

[ois0886]

Summary

• Move the remaining hardcoded user-facing strings in TopicScreen into topic string resources.
• Keep the visible English text unchanged while making the strings consistent with the rest of the app and ready for localization.

Fixes #2115

Test plan

• ./gradlew spotlessCheck
• ./gradlew :feature:topic:impl:testDemoDebugUnitTest
• ./gradlew :feature:topic:impl:lintDemoDebug :feature:topic:api:lintDemoDebug
• ./gradlew :feature:topic:impl:connectedDemoDebugAndroidTest -Pandroid.testInstrumentationRunnerArguments.class=com.google.samples.apps.nowinandroid.feature.topic.impl.TopicScreenTest

[gemini-code-assist]

Code Review

This pull request replaces hardcoded strings in the TopicScreen with localized string resources. The feedback recommends using sentence case for the string definitions and applying uppercase transformations within the UI layer to better support localization and separate content from presentation.

[gemini-code-assist]

Avoid hardcoding uppercase text in string resources. Casing is a presentation detail that should be handled by the UI layer. This ensures better support for localization, as capitalization rules vary by language and some scripts do not use it at all. Using sentence case here also makes these strings consistent with the other new strings in this file.

Suggested change

	<string name="feature_topic_api_following">FOLLOWING</string>
	<string name="feature_topic_api_not_following">NOT FOLLOWING</string>
	<string name="feature_topic_api_following">Following</string>
	<string name="feature_topic_api_not_following">Not following</string>

[ois0886]

Thanks for the suggestion. I updated the follow-state strings to sentence case in the resources.

[gemini-code-assist]

To maintain the current all-caps design while using sentence-case string resources, apply the .uppercase() transformation in the UI. This separates the content from its presentation and follows Android best practices for internationalization.

Suggested change

	Text(stringResource(TopicR.string.feature_topic_api_following))
	} else {
	Text("NOT FOLLOWING")
	Text(stringResource(TopicR.string.feature_topic_api_not_following))
	Text(stringResource(TopicR.string.feature_topic_api_following).uppercase())
	} else {
	Text(stringResource(TopicR.string.feature_topic_api_not_following).uppercase())

[ois0886]

Thanks, this makes sense. I kept the visible all-caps presentation in the UI and used uppercase(Locale.getDefault()) to match the existing production pattern in NewsResourceCard.