[201911] [Systemd] Upgrade systemd to fix timer elapsed issue (#12485)

Upgrade systemd to fix timer elapsed issue.

#### Why I did it
On 201911 release, snmp.timer become elapsed status and snmp.service will not be trigger by snmp.timer:

● snmp.service - SNMP container
Loaded: loaded (/usr/lib/systemd/system/snmp.service; static; vendor preset: enabled)
Active: inactive (dead)
● snmp.timer - Delays snmp container until SONiC has started
Loaded: loaded (/usr/lib/systemd/system/snmp.timer; enabled; vendor preset: enabled)
Active: active (elapsed) since Wed 2022-08-03 18:12:59 UTC; 2 months 17 days ago

This issue caused by systemd bug: https://github.com/systemd/systemd/pull/10778/files

This issue can be reproduce with following steps:
1. reboot system.
2. continusly run following commands till  timer elapsed:
systemctl status snmp.timer
sudo systemctl daemon-reload

#### How I did it
Install latest version systemd from offical backport source.

#### How to verify it
Pass all test case.
Manually check reproduce steps, verify the issue fixed.

#### Which release branch to backport (provide reason below if selected)

<!--
- Note we only backport fixes to a release branch, *not* features!
- Please also provide a reason for the backporting below.
- e.g.
- [x] 202006
-->

- [ ] 201811
- [ ] 201911
- [ ] 202006
- [ ] 202012
- [ ] 202106
- [ ] 202111
- [ ] 202205

#### Description for the changelog
Upgrade systemd to fix timer elapsed issue.

#### Ensure to add label/tag for the feature raised. example - PR#2174 under sonic-utilities repo. where, Generic Config and Update feature has been labelled as GCU.

#### Link to config_db schema for YANG module changes
<!--
Provide a link to config_db schema for the table for which YANG model
is defined
Link should point to correct section on https://github.com/Azure/sonic-buildimage/blob/master/src/sonic-yang-models/doc/Configuration.md
-->

#### A picture of a cute animal (not mandatory but encouraged)

build_debian.sh

@@ -335,7 +335,7 @@ sudo LANG=C chroot $FILESYSTEM_ROOT bash -c "find /usr/share/i18n/locales/ ! -na
 # Install certain fundamental packages from stretch-backports in order to get
 # more up-to-date (but potentially less stable) versions
 sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get -y -t stretch-backports install \
-    picocom
+    picocom libsystemd0 systemd
 
 if [[ $CONFIGURED_ARCH == amd64 ]]; then
     sudo LANG=C DEBIAN_FRONTEND=noninteractive chroot $FILESYSTEM_ROOT apt-get -y download \