net_lwip_webserver example fix and improvement #3129

Job	Run time
set-matrix	5s
make-os (macos-latest) / family (stm32h7)	51s
make-os (windows-latest) / family (stm32h7)	1m 48s
arm-iar	6m 13s
make	0s
cmake (aarch64-gcc) / family (broadcom_64bit)	28s
cmake (arm-gcc) / family (broadcom_32bit)	31s
cmake (msp430-gcc) / family (msp430)	22s
cmake (arm-gcc) / family (da1469x)	48s
cmake (arm-gcc) / family (imxrt)	4m 45s
cmake (arm-gcc) / family (kinetis_k kinetis_kl kinetis_k32l2)	2m 13s
cmake (riscv-gcc) / family (ch32v10x ch32v20x ch32v307 fomu gd32vf103)	1m 45s
cmake (arm-gcc) / family (lpc11 lpc13 lpc15)	1m 10s
cmake (arm-gcc) / family (lpc17 lpc18 lpc40 lpc43)	2m 49s
cmake (arm-gcc) / family (lpc51 lpc54 lpc55)	2m 37s
cmake (arm-gcc) / family (max32650 max32666 max32690 max78002)	3m 19s
cmake (arm-gcc) / family (mcx)	1m 26s
cmake (arm-gcc) / family (mm32)	55s
cmake (arm-gcc) / family (msp432e4 tm4c)	55s
cmake (arm-gcc) / family (nrf)	3m 49s
cmake (arm-gcc) / family (ra)	2m 44s
cmake (arm-gcc) / family (rp2040)	5m 8s
cmake (arm-gcc) / family (samd11 saml2x)	1m 25s
cmake (arm-gcc) / family (samd21)	3m 40s
cmake (arm-gcc) / family (samd5x_e5x samg)	3m 3s
cmake (arm-gcc) / family (stm32f0 stm32f1 stm32f2 stm32f3)	2m 29s
cmake (arm-gcc) / family (stm32f4)	3m 32s
cmake (arm-gcc) / family (stm32f7)	2m 11s
cmake (arm-gcc) / family (stm32g0 stm32g4 stm32h5)	2m 25s
cmake (arm-gcc) / family (stm32h7)	2m 48s
cmake (arm-gcc) / family (stm32l0 stm32l4)	2m 0s
cmake (arm-gcc) / family (stm32u5 stm32wb)	2m 28s
cmake (arm-gcc) / family (xmc4000)	52s
	1h 11m 34s

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