Improve wrapped key loader

[mohitc1]

AndroidWrappedKeyLoader currently has code cache secret key in memory, but there are multiple instances of AndroidWrappedKeyLoader active (one per BrokerPlatformComponents). So, each object gets is own cache and there's no benefit of caching. Moreover, this makes keystore reads more frequent and concurrent.

Changes:
Update caching logic in AndroidWrappedKeyLoader by static ConcurrentHashMap so cache is shared across all ConcurrentHashMap. This fixes caching (effective) logic and reduces keystore unwrap and decrypt calls. A good side effect of this would be lesser number of failures due to Keystore unwrap calls that we have seen.

AndroidKeyStoreUtil changes:
Load keystore always instead of caching, as it is recommended to not cache it statically.

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Pull Request Overview

This PR centralizes secret key caching across all AndroidWrappedKeyProvider instances using a static ConcurrentHashMap, and ensures the Android KeyStore is reloaded on each access rather than statically cached.

• Use a shared static ConcurrentHashMap<String, SecretKey> in AndroidWrappedKeyProvider for effective cross-instance caching
• Remove per-instance CachedData and introduce getKeyFromCache/clearKeyFromCache helpers
• Update AndroidKeyStoreUtil to always load a fresh KeyStore on demand
• Adjust Android test suites and update changelog.txt accordingly

Comments suppressed due to low confidence (3)

common/src/main/java/com/microsoft/identity/common/crypto/AndroidWrappedKeyProvider.java:186

• [nitpick] The log message "Key not in cache is empty, loading key from storage" is confusing. Consider renaming it to something clearer like "Cache miss: loading key from storage".

        Logger.info(methodTag, "Key not in cache is empty, loading key from storage");

common/src/main/java/com/microsoft/identity/common/crypto/AndroidWrappedKeyProvider.java:176

• Add a unit test to verify that cache entries are evicted when AndroidKeyStoreUtil.canLoadKey(...) returns false or when the key file is missing, to ensure the invalidation logic is correct.

        if (!sSkipKeyInvalidationCheck &&

common/src/main/java/com/microsoft/identity/common/crypto/AndroidWrappedKeyProvider.java:132

• [nitpick] Consider adding Javadoc to getKeyFromCache() (and clearKeyFromCache()) to clarify their intended use and thread-safety guarantees.

    /* package */ SecretKey getKeyFromCache() {