Espressif: Fix interrupts in UART workflow

[prplz]

Fixes uart workflow on espressif not being able to interrupt code and slowness at the "press any key" prompt.

While I was working on this I noticed a board with a neopixel status LED didnt suffer from the slowness due to incorect expansion of CIRCUITPY_STATUS_LED so I fixed that too.

[tannewt]

Please explain why this fixes the UART issue. Ideally the UART code shouldn't need special cases for the debug UART.

[prplz]

First bug: with uart workflow (esp32-c3 boards mostly), pressing ctrl+c in the repl does nothing, while it should schedule a keyboard interrupt. In the usb cdc workflow this is done by setting a "wanted" char of ctrl+c and calling mp_sched_keyboard_interrupt when it's seen. Note the wanted char is only listened for on the first cdc interface (usb_cdc.console and not usb_cdc.data). Short of re-writing the uart code to use our own queues, the easiest way to do this same behaviour on uart was using an event listener task with the uart's pattern detection (uart_enable_pattern_det_baud_intr).

Second bug: like in #6046, the uart console respond slowly to the "press any key prompt". This is fixed by waking up the main task on the data event.

Third bug: I noticed while writing these fixes that a board with a neopixel status LED didn't suffer from the slow any key response bug. I tracked it down to an incorrect expansion of CIRCUITPY_STATUS_LED which was causing the loop to be constantly woken up, so I added parenthesis to make it expand correctly.

I put the event listener behind an ifdef because it is only used on boards that have a debug uart, and it should only act on the uart hosting the console.

[tannewt]

Thank you for the explanation! Would you mind including a version of it before event_task to explain how it works there?

[prplz]

I made the discussed changes: the task now starts for every uart and added some more comments. Let me know if theres anything else I should do.

[dhalbert]

Thanks, merging based on @tannewt's review.