* Replace `MatrixClient.keyBackupKeyFromRecoveryKey` by `decodeRecoveryKey`
* Replace `MatrixClient.isValidRecoveryKey` by local check with `decodeRecoveryKey`
* Replace old `decodeRecoveryKey` import
* Remove `matrix-js-sdk/src/crypto/recoverykey` import of eslint exception
* Add tests for `RestoreKeyBackupDialog`