Properly clean up on SimpleMDNS::end #3083

Job	Run time
Spelling, Style, Boards, Package, PIO	2m 53s
Build 2	7m 22s
Build 1	7m 17s
Build 5	6m 33s
Build 4	7m 21s
Build 0	6m 33s
Build 3	8m 10s
Mac (macOS-15-intel)	3m 2s
Build RP2350 4	6m 59s
Build RP2350 1	6m 27s
Build RP2350 3	7m 33s
Build PlatformIO Examples	3m 40s
Build RP2350 2	6m 59s
Build RP2350 5	5m 56s
Build Every Variant 1	6m 42s
Build TinyUSB Examples	4m 4s
Build Every Variant 0	6m 33s
Mac (macOS-14)	2m 35s
Windows	3m 38s
Build RP2350-RISCV 2	7m 2s
Build RP2350-RISCV 0	6m 40s
Build Every Variant 3	6m 35s
Build RP2350 0	7m 19s
Build RP2350-RISCV 1	6m 13s
Build Every Variant 2	6m 29s
Build RP2350-RISCV 3	7m 23s
Build RP2350-RISCV 4	6m 39s
Build RP2350-RISCV 5	5m 43s
	2h 50m 20s

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