espressif: drop CONFIG_FREERTOS_WATCHPOINT_END_OF_STACK from the example defaults (#4236)

On a RISC-V target (P4, S31) with a debugger attached, every context switch
re-arms the stack watchpoint through a semihosting ebreak, so openocd halts
the core at task rate: USB service stops, the attach itself sometimes lands
in the panic handler, and the chip boot-loops after openocd exits. ESP-IDF
leaves the option off by default and the canary stack check stays on.
Dropping it frees one hardware trigger and shrinks configMINIMAL_STACK_SIZE
by 60 bytes, so tasks sized from that constant get smaller allocations,
partly offset by the up-to-60-byte region the watchpoint reserved.