T7729: Build accel-ppp-ng remove extra whitespace

[sever-sever]

Change summary

Build accel-ppp-ng remove extra whitespace to fix build binaries

Fixes:

CMake Error: The source directory "/__w/vyos-reusable-workflows/vyos-reusable-workflows/vyos-build/scripts/package-build/linux-kernel/accel-ppp-ng/build/ " does not exist.
Specify --help for usage, or press the help button on the CMake GUI.
./build-accel-ppp-ng.sh: 57: -DCPACK_TYPE=Debian12: not found
make: *** No targets specified and no makefile found.  Stop.
CPack Error: CPack project name not specified
mv: cannot stat 'accel-ppp*.deb': No such file or directory

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Code style update (formatting, renaming)
• Refactoring (no functional changes)
• Migration from an old Vyatta component to vyos-1x, please link to related PR inside obsoleted component
• Other (please describe):

Related Task(s)

• https://vyos.dev/T7729

Related PR(s)

Checklist:

• I have read the CONTRIBUTING document
• I have linked this PR to one or more Phabricator Task(s)
• My commit headlines contain a valid Task id
• My change requires a change to the documentation
• I have updated the documentation accordingly

[github-actions]

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