Allow access to `getApplicationConfig` for bots

[septatrix]

Currently bots cannot get the application config. As a result bots need to hardcode some values. A recent example is the amount of poll options which was increased (see 11191d82dec3bc42bf57d8c96a9a6c890d546531) but bots were hardcoded to prevent users to create more than 10 choices as anything higher historically failed. Exposing the app config allows to remove those constants in favor of dynamically obtained values.

[levlam]

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