Fixes flutter/flutter#83213.
Maybe fixes flutter/flutter#80938

We restart the IME when the framework changes the composing region. When this happens during a batch edit the old connection doesn't get to call endBatchEdit so we need to clean that up. Currently if that happens the framework will never be updated (as the batch edit count is always going to be > 0).

Per Android API docs:

public abstract void closeConnection ()
Editor authors: You can clear all the nested batch edit right now and you no longer need to handle subsequent callbacks on this connection, including beginBatchEdit()}. Note that although the system tries to call this method whenever possible, there may be a chance that this method is not called in some exceptional situations.

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