mqtt: Improve handling of multiple PDU parsing

[jlucovsky]

Continuation of #10107

Issue: 6592

Link to redmine ticket: 6592

Describe changes:

• Parse PDU instead of entire stream

Updates:

• Reflect remaining byte count (per review comment)

Provide values to any of the below to override the defaults.

To use a pull request use a branch name like pr/N where N is the
pull request number.

Alternatively, SV_BRANCH may also be a link to an
OISF/suricata-verify pull-request.

SV_REPO=
SV_BRANCH=pr/1609
SU_REPO=
SU_BRANCH=
LIBHTP_REPO=
LIBHTP_BRANCH=

[jlucovsky]

@catenacyber Could you verify the s-v tests? They pass in master and with the changes in this PR.

[suricata-qa]

Information:

ERROR: QA failed on SURI_TLPW2_autofp_suri_time.

ERROR: QA failed on SURI_TLPW1_suri_time.

ERROR: QA failed on SURI_TLPW1_files_sha256.

field	baseline	test	%
	SURI_TLPW2_autofp_stats_chk
.uptime	181	192	106.08%
	SURI_TLPW1_stats_chk
.uptime	137	144	105.11%
	SURI_TLPR1_stats_chk
.app_layer.error.http.parser	1108	724	65.34%

Pipeline 17738

[catenacyber]

Could you verify the s-v tests? They pass in master and with the changes in this PR.

Yes, you should have tests failing in master ;-) cf comment posted on the SV PR

[jlucovsky]

Continued in #10262