Backport of openldap for jammy, noble and questing

[Lena Voytek]

[Impact]

This bug tracks the following MRE updates for the OpenLDAP package:

* MRE for latest stable OpenLDAP 2.5.x release, 2.5.20 (last planned 2.5 release).
* MRE for latest stable OpenLDAP 2.6.x release, 2.6.10 (new LTS).

See https://<email address hidden>/thread/2QQNVWPUUG54JM7FGQHMMF3H4KS2PPKQ/ and https://<email address hidden>/thread/H2THDP3JYECCPJ45BEGGEYYL44YRHUK7/

These updates are a best effort to only include bug fixes, following the
SRU policy exception defined at https://documentation.ubuntu.com/sru/en/latest/reference/exception-OpenLDAP-Updates/.

[Major Changes]

See the list of bugs fixed for 2.5.x here:
- https://git.openldap.org/openldap/openldap/-/blob/OPENLDAP_REL_ENG_2_5/CHANGES
  - https://<email address hidden>/thread/IXITZR4E6P5LAZ5FFQPE2222CRGKJVYS/
For 2.6.x:
- https://git.openldap.org/openldap/openldap/-/blob/OPENLDAP_REL_ENG_2_6/CHANGES
  - https://<email address hidden>/thread/QQ3AAIAKT6VVMGM7T2PRLGOKW4PABGQK/

- we have a delta to fix bug #2090806, which is now in 2.6.9.

[Test Plan]

See https://documentation.ubuntu.com/sru/en/latest/reference/exception-OpenLDAP-Updates/#qa

1. Upstream gitlab pipeline results:

- 2.6.10: https://git.openldap.org/openldap/openldap/-/pipelines/5935
- 2.5.20: https://git.openldap.org/openldap/openldap/-/pipelines/5933

2. Upstream "call for testing":

- 2.5.20: https://<email address hidden>/message/NFTXNTUS5WQFOPWHCGQFI2PFLJM22II5/
- 2.6.10: https://<email address hidden>/message/HGBDBYJ5O765LSAOLTPXNFFX3ZNBK7IR/

3. As described in the MRE page for OpenLDAP, the test plan is to
   build the package in a PPA and make sure that (a) all build-time
   tests pass and (b) all autopkgtest runs (from reverse dependencies)
   also pass.

* Build log (amd64) confirming that the build-time testsuite has been
  performed and completed successfully:
  - <link to build log(s)>

* Test results:
  - <autopkgtest results and discussion>

[Where problems could occur]

Upstream tests are always executed during build-time. There are many
reverse dependencies whose dep8 tests depend on OpenLDAP so the coverage
is good. Nevertheless, there is always a risk for something to break
since we are dealing with a microrelease upgrade. Whenever a test
failure is detected, we will be on top of it and make sure it doesn't
affect existing users.

As usual we test and prep from the PPA and then push through
SRU/Security as applicable.

* Current versions in supported releases that got updates:
  - openldap | 2.6.7+dfsg-1~exp1ubuntu8.2 | noble-updates
  - openldap | 2.5.19+dfsg-0ubuntu0.22.04.1 | jammy-updates

[Other Info]

This is a recurring effort. For reference, here are previous OpenLDAP SRU backports:

* LP: #1977627
* LP: #1983618
* LP: #2007625
* LP: #2027079
* LP: #2029170
* LP: #2040465
* LP: #2067745
* LP: #2112527

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.