Use uint8_t instead of uint32_t for 8-bit values on mitsubishi

[DAVe3283]

What does this implement/fix?

The mitsubishi component was using a uint32_t array to build & process 8-bit messages.
This was causing some printf formatting issues on ESP-IDF, and wastes RAM on all platforms.

This PR switches to using uint8_t instead, solving both issues.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Other

Test Environment

• ESP32
• ESP32 IDF
• ESP8266
• RP2040
• BK72xx
• RTL87xx

Example entry for config.yaml:

# Example config.yaml
esphome:
  name: esp32c6test1
  friendly_name: esp32c6test1

esp32:
  board: esp32-c6-devkitc-1
  variant: esp32c6
  framework:
    type: esp-idf
    version: 5.2.1 # Need at least 5.1 for ESP32-C6
    platform_version: 6.7.0 # Need at least 6.4 for ESP32-C6
    sdkconfig_options:
      CONFIG_ESPTOOLPY_FLASHSIZE_4MB: y # default is 4MB but https://github.com/esphome/issues/issues/5404

logger:
  level: VERY_VERBOSE

api:
wifi:
  ssid: !secret wifi_ssid
  password: !secret wifi_password
  ap:
captive_portal:


climate:
  - platform: mitsubishi
    name: Mitsubishi
    supports_dry: "true"
    supports_fan_only: "true"
    horizontal_default: "left"
    vertical_default: "down"

Checklist:

• The code change is tested and works locally.
• Tests have been added to verify that the new code works (under tests/ folder).

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in esphome-docs.

[probot-esphome]

Hey there @RubyBailey, mind taking a look at this pull request as it has been labeled with an integration (mitsubishi) you are listed as a code owner for? Thanks!
_{^{(message by CodeOwnersMention)}}

[kbx81]

Awesome, thanks! 🍻

[RubyBailey]

Thank you. That’s great. 🍻🍻