Fix Windows installer build by removing libboost DLLs

[acolwell]

Msys2 has updated to a version of boost that no longer includes the libboost-regex-mt and libboost-system-mt DLLs. This change removes references to these DLLs so that the installer build stops trying to find them and failing.

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PR Description

What type of PR is this? (Check one of the boxes below)

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Improvement (non-breaking change which does not add functionality nor fixes a bug but improves Natron in some way)
• Breaking change (fix or feature that would cause existing functionality to change)
• My change requires a change to the documentation
  • I have updated the documentation accordingly

What does this pull request do?

Fixes the Windows installer build by removing 2 boost DLLs that are no longer included in Msys2.

Have you tested your changes (if applicable)? If so, how?

Yes. I verified the Windows installer successfully builds again (https://github.com/acolwell/Natron/actions/runs/11138194808)