boards: thingy52_nrf52832: additional led aliases
boards: thingy52_nrf52832: additional led aliases

This PR updates the `thingy52_nrf52832` dts to add two additional
aliases for leds 1 & 2.

Why:
In a university course, alot of students use this board with Zephyr
and have wondered why many boards provide dts aliases for
additional leds (ex [1][2]), yet, this only has an alias
for the single led. The PR adds required led
aliases to make working with the leds on this board a
little bit quicker/easier.

Testing:
	* `./scripts/twister -p thingy52_nrf52832`
	* Hardware verification using the gpio_api to toggle all leds.

Edit: Fixup commit msg line length

[1] boards/arm/particle_boron/dts/mesh_feather.dtsi
[2] boards/arm/arduino_nano_33_ble/arduino_nano_33_ble.dts

Signed-off-by: Wilfred Mallawa <e9141b0d3b8bc048c4be34b9bda1d9c74f7e7671@uqconnect.edu.au>

finikorg/zephyr,zephyrproject-rtos/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,finikorg/zephyr,finikorg/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr