TOOL-22328 Fix auto-updates for generic kernel on 5.15

[prakashsurya]

Problem

Automated syncs with upstream fail with the following error:

04:01:47  Running: get_kernel_version_for_platform_from_apt generic
04:01:47  note: upstream tag prefix used: Ubuntu-5.15-5.15.0-78
04:01:47  tag with prefix Ubuntu-5.15-5.15.0-78 not found.

See here

The tags have "hwe" in them, which the automation isn't using due to the bug:

> g tag | grep Ubuntu-5.15-5.15.0-78
> g tag | grep Ubuntu-hwe-5.15-5.15.0-78
Ubuntu-hwe-5.15-5.15.0-78.85_20.04.1

Testing

See here