[build] Stop installing python3-regex via apt to avoid pip uninstall-no-record-file failure (#28182)

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#### Why I did it
`target/python-wheels/trixie/sonic_utilities-1.2-py3-none-any.whl-install` and `sonic-marvell-prestera-armhf.bin` started failing during the `sonic-utilities` wheel install with:
```
Cannot uninstall regex 2024.11.6
╰─> The package's contents are unknown: no RECORD file was found for regex.

 hint: The package was installed by debian. You should check if it can uninstall the package.
```
`sonic-slave-trixie` and `sonic_debian_extension` installed `python3-regex` from debian apt repo in dist-packages folder without a pip RECORD file, so pip cannot uninstall it later.
When the sonic-utilities wheel pulls in a newer regex - currently triggered by sonic-utilities -> docker-image-py (the unbounded `docker-image-py>=0.1.10` dependency now resolves to `0.2.0`, published 2026-06-29, which requires `regex>=2026.6.28`) - pip failed on `uninstall-no-record-file`.
##### Work item tracking
- Microsoft ADO **(number only)**:

#### How I did it
- removed `python3-regex` from `sonic-slave-trixie/Dockerfile.j2`
- remove `python3-regex` from `sonic_debian_extension.j2`
#### How to verify it

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- [ ] 202605
- [ ] 202608

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Signed-off-by: Sonic Build Admin <sonicbld@microsoft.com>

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Author: mssonicbld

files/build_templates/sonic_debian_extension.j2

@@ -224,7 +224,12 @@ sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get -y in
 install_pip_package {{sonic_yang_mgmt_py3_wheel_path}}
 
 # Install some dependencies for pyangbind
-sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get -y install python3-lxml python3-regex
+# python3-regex is intentionally NOT installed here. The Debian apt package
+# (python3-regex) installs into dist-packages without a pip RECORD file, so pip
+# cannot uninstall/upgrade it later. When a downstream wheel (e.g. sonic-utilities
+# via docker-image-py) requires a newer regex, pip fails with "uninstall-no-record-file".
+# Let pip own regex instead: it is pulled in transitively by pyangbind below.
+sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get -y install python3-lxml
 
 sudo https_proxy=$https_proxy LANG=C chroot $FILESYSTEM_ROOT pip3 install pyangbind==0.8.7
 sudo https_proxy=$https_proxy LANG=C chroot $FILESYSTEM_ROOT pip3 uninstall -y enum34

sonic-slave-trixie/Dockerfile.j2

@@ -546,6 +546,9 @@ RUN apt-get remove -y libnl-3-200
 
 RUN eatmydata apt-get -y build-dep openssh
 
+# Let pip own these (avoid apt vs pip no-RECORD uninstall conflicts)
+RUN eatmydata apt-get remove -y python3-regex || true
+
 # Build fix for ARM64 and ARMHF /etc/debian_version
 {%- if CONFIGURED_ARCH == "armhf" or CONFIGURED_ARCH == "arm64" %}
 RUN eatmydata apt upgrade -y base-files libc-bin=$(dpkg-query -W -f '${Version}' libc-bin)