[FEATURE] Add TCA9458a Stub to Typings

[Mikefly123]

Story

• As a developer
• I want to ensure consistent and safe use of types
• So that we don't cause unexpected errors at runtime

Acceptance Criteria

• Create a Stub for TCA9458a Channel Types

Technical Details

Some of the I2C devices that we use in the kit are not connected to the microcontroller's native I2C buses (which present as objects of i2c type. Sensors in places like the solar panels are connected first through a TCA9458a multiplexer, which generates a spoof of the i2c device with the type tca9458a_channel.

This throws the type checker for a loop and ideally we would like that not to happen!

[Mikefly123]

This was dealt with in #285 and #283