[BUG] Address review issues on PR 28836

[bzbarsky-apple]

Reproduction steps

See #28836 (review) @lpbeliveau-silabs

Bug prevalence

Always

GitHub hash of the SDK that was being used

1ed3897

Platform

core

Platform Version(s)

No response

Anything else?

No response

[bzbarsky-apple]

Note: #29033 did not fully address this, both because it ignored #28836 (comment) and because of #29076 (comment) @andy31415 @jmartinez-silabs

[lpbeliveau-silabs]

Linking the spec issue opened here: https://github.com/CHIP-Specifications/connectedhomeip-spec/issues/7536
as well as the null level specific issue opened here: #29185