remove task_arena from lab04 (#680)

* add stm32u5 debug image.

* fix stm32u5 debug image.

* update lab01

* change defmt and cortex-m version.

* Update website/lab/01/index.mdx

Co-authored-by: Alexandru Radovici <msg4alex@gmail.com>

* add defmt error snippet.

* update cargo.toml for stm32u5 and add waiting explanation for stm32.

* add informations about exti and update cargo.toml for rp2.

* Update index.mdx with RP2350 and RP2040 dependencies

* Remove comments from dependencies in index.mdx

* Update website/lab/02/index.mdx

Co-authored-by: Alexandru Radovici <msg4alex@gmail.com>

* add pin `D10` to lab03

* add analog pins to lab03

* delete `Config` warning for ADC and PWM

* delete the note about PWM channels

* add `set_polarity` function to lab

* add lab improvements

* Remove `task_arena` from tip

Clarified instructions on task instances and pool size for LED control.

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Co-authored-by: Alexandru Radovici <msg4alex@gmail.com>

Author: genan2003

website/lab/04/index.md

@@ -431,7 +431,7 @@ while start_time.elapsed().as_millis() < time_interval {}
 
 You should notice that one of the tasks is not running. Why? (**1p**)
     :::tip
-    Use a different task instance for each LED. You can spawn multiple instances of the same task, however you need to specify the pool size with `#[embassy_executor::task(pool_size = 2)]`. Take a look at [task-arena](https://docs.embassy.dev/embassy-executor/git/std/index.html#task-arena) for more info.
+    Use a different task instance for each LED. You can spawn multiple instances of the same task, however you need to specify the pool size with `#[embassy_executor::task(pool_size = 2)]`.
     Use [`AnyPin`](https://docs.embassy.dev/embassy-stm32/git/stm32u545re/gpio/struct.AnyPin.html) and blinking frequency parameters for the task. 
     :::