Fix creating telegram notifier with no ptz set

[matvey00z]

Fixes #997

[netlify]

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[roflcoopter]

There is potentially a race condition going on here.
If you intend to use the PTZ component but it sets up after the Telegram component, TelegramPTZ wont be instantiated.

Another more fail-safe approach would be a small loop that checks the dict vis.data[LOADING] and vis.data[LOADED] to see if it contains the ptz key. Or it could simply raise ComponentNotReady which will cause Viseron to retry setup of the component