Update save button icon and include snackbar message

[Divinelink]

Summary

This pull request updates the save button icon to make it distinguishable from the watchlist button and also adds a snackbar message when a movie or show is added or removed from the saved items.

[github-actions]

	Warnings
⚠️	6 changed file(s) have less than 100% line coverage.

✅ Code coverage: 78.46%

Metric	Covered	Missed	Total	Coverage
Lines	19170	5264	24434	78.46%

_{Line coverage from unit tests (Kover). Threshold: 60%.}

📂 Changed files coverage

File	Covered	Missed	Coverage
SearchContent.kt	44	28	🟡 61.1%
MediaImage.kt	29	13	🟡 69.0%
DetailsContent.kt	186	41	🟡 81.9%
SaveButton.kt	42	2	🟡 95.5%
PersonScreen.kt	60	2	🟡 96.8%
ActionMenuContent.kt	57	1	🟡 98.3%
SearchViewModelTestRobot.kt	—	—	⚪ not in report
SearchContentTest.kt	—	—	⚪ not in report

Generated by 🚫 Danger Kotlin against 19041ce