Mirror Text for MAX7219DIGIT Component

**Describe the problem you have/What new integration you would like**
There is currently no way of mirroring the output for the MAX7219DIGIT Display Component.

**Please describe your use case for this integration and alternatives you've tried:**
It is for building a Head-Up-Display, where the dotMatrix LEDS are displayed on a transparent acrylic plate. So the output needs to be mirrored in order to display properly on the acrylic plate.

I tried using Lambda "it.transform(MD_MAX72XX::TFUD); // flip upside down -- for heads up display" , but this ended up with compilation errors.

**Additional context**

Inspired by a HUD Clock on Thingiverse : https://www.thingiverse.com/thing:5660617

Start by locating the ESPHome MAX7219DIGIT component and its display-transformation entry point; compare it with the MD_MAX72XX::TFUD lambda mentioned in the report. Confirm that mirrored output works for the transparent-acrylic HUD use case and that the component builds without the reported compilation error.

Written by the indexing model from the issue text.