Memfault uses a deprecated Zephyr type: `z_arch_esf_t`

[carlescufi]

z_arch_esf_t is now struct arch_esf

See:

zephyrproject-rtos/zephyr#73593

[noahp]

Thank you @carlescufi for reporting- I've pushed a branch in #75 for verification, let us know if it's working and we'll publish an official release of the SDK.

[noahp]

Fix was published in SDK release 1.12.0, thanks again for reporting the issue!