saveSession and loadSession do not accept file:// URI's.

[Vali-98]

Unlike initLlama, saveSession and loadSession both do not accept paths prefixed with file://.

Though this is a minor issue, it does hurt users of expo-filesystem which always prefixes its documentDirectory with file://, unlike ReactNativeBlobUtil used in the example app. Attempting to use documentDirectory from expo-filesystem results in a file not found error.

At the moment, this is simply fixed by replacing file:// with an empty string, however, consistency between initLlama, saveSession and loadSession path parsing would be ideal.