The API documentation for cipher_migrate is here: SQLCipher API - Full Database Encryption PRAGMAs, Functions, and Settings | Zetetic
You’ll want to follow the guidance mentioned in the API documentation for how to determine whether to perform the migration as it is expensive.
There’s an example of calling cipher_migrate in the postKey hook here: sqlcipher-android-tests/app/src/main/java/net/zetetic/tests/CipherMigrateTest.java at master · sqlcipher/sqlcipher-android-tests · GitHub
From your code it looks like you’re hard coding a key value. We strongly recommend against doing that. There’s some information about Key Material and Selection, along with some technical guidance in these posts: