Add darwin test for general diagnostics cluster, and fix incorrect reinterpret_cast that got added

[bzbarsky-apple]

Problem

General diagnostics did not get added to our various chip-tools (darwin and example).

Summary of Changes

Add it to the tools, fix it to compile correctly and pass the tests.

Fixes #6801

[todo]

CHAR_STRING not supported yet in structs.

connectedhomeip/src/app/zap-templates/zcl/custom-types.xml

Lines 64 to 68 in 8de069c

	// TODO: CHAR_STRING not supported yet in structs.
	<item name="Name" type="OCTET_STRING" length="32"/>
	<item name="FabricConnected" type="BOOLEAN"/>
	<item name="OffPremiseServicesReachableIPv4" type="BOOLEAN"/>
	<item name="OffPremiseServicesReachableIPv6" type="BOOLEAN"/>

---

This comment was generated by todo based on a TODO comment in 8de069c in #6804. cc @bzbarsky-apple.

[woody-apple]

@bzbarsky-apple ?

[github-actions]

Size increase report for "esp32-example-build" from f4b00be

File	Section	File	VM
chip-all-clusters-app.elf	.flash.text	-4	-4

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-all-clusters-app.elf and ./pull_artifact/chip-all-clusters-app.elf:

sections,vmsize,filesize
.debug_info,0,3891
.debug_loc,0,1945
.debug_line,0,1937
.debug_str,0,480
.debug_frame,0,96
.debug_aranges,0,32
.debug_ranges,0,32
.xt.prop._ZTVN4chip11DeviceLayer37DeviceNetworkProvisioningDelegateImplE,0,-1
.flash.text,-4,-4

Comparing ./master_artifact/chip-pigweed-app.elf and ./pull_artifact/chip-pigweed-app.elf:

sections,vmsize,filesize