Bump tplink python-kasa dependency to 0.7.6

[sdb9696]

Proposed change

Bump python-kasa to 0.7.6.

A lot of the changes in this release are for the new experimental devices which are disabled for HA. The main changes relevant to HA in this release is the try_connect_all function related to #128994

Tweak to type checking needed as discover_single can now return None if a callback is passed to the function for handling unsupported devices.

0.7.6 release notes

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[home-assistant]

Hey there @rytilahti, @bdraco, mind taking a look at this pull request as it has been labeled with an integration (tplink) you are listed as a code owner for? Thanks!

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