Enable use of nullptr for 0 length plaintext/ciphertext in crypto

[pan-apple]

Problem

• Fixes CASE resumption fails with openssl due to null pointers being used #10190

Change overview

OpenSSL APIs do not support using nullptr for 0 length plaintext for encrypt, and 0 length cipher-text for decrypt operations. Expectation is to use an empty string instead of nullptr.

This PR uses a temporary empty string if the user has provided a nullptr and 0 length for the corresponding value. It also adds more checks and tests to ensure that API behaves as expected.

Testing

Added more unit tests to CHIPCryptoPALTest suite.

[github-actions]

Size increase report for "gn_qpg-example-build" from ed8d28c

File	Section	File	VM
chip-qpg6100-lighting-example.out	.text	24	24

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-qpg6100-lighting-example.out.map and ./pull_artifact/chip-qpg6100-lighting-example.out.map:

BLOAT EXECUTION FAILED WITH CODE 1:
bloaty: unknown file type for file './pull_artifact/chip-qpg6100-lighting-example.out.map'

Comparing ./master_artifact/chip-qpg6100-lighting-example.out and ./pull_artifact/chip-qpg6100-lighting-example.out:

sections,vmsize,filesize
.debug_line,0,29
.text,24,24
.debug_info,0,2
.debug_str,0,1
[Unmapped],0,-24

[github-actions]

Size increase report for "nrfconnect-example-build" from ed8d28c

File	Section	File	VM
chip-shell.elf	text	24	24
chip-shell.elf	device_handles	-8	-8
chip-lock.elf	text	24	24
chip-lock.elf	device_handles	-8	-8

Full report output

BLOAT REPORT

Files found only in the build output:
    report.csv

Comparing ./master_artifact/chip-shell.elf and ./pull_artifact/chip-shell.elf:

sections,vmsize,filesize
.debug_line,0,26
text,24,24
.debug_info,0,2
.debug_loc,0,-4
device_handles,-8,-8

Comparing ./master_artifact/chip-lock.elf and ./pull_artifact/chip-lock.elf:

sections,vmsize,filesize
.debug_line,0,30
text,24,24
.debug_info,0,2
device_handles,-8,-8

[github-actions]

Size increase report for "esp32-example-build" from ed8d28c

File	Section	File	VM
chip-all-clusters-app.elf	.flash.text	48	48

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_line,0,97
.flash.text,48,48
.debug_frame,0,8
.debug_loc,0,4
.riscv.attributes,0,-1
.debug_abbrev,0,-20
.debug_ranges,0,-24
[Unmapped],0,-48