New-DbaDbSnapshot - Support special characters in database name

[niphlod]

Please read -- recent changes to our repo

On November 10, 2022, we removed some bloat from our repository (for the second and final time). This change requires that all contributors reclone or refork their repo.

PRs from repos that have not been recently reforked or recloned will be closed and @potatoqualitee will cherry-pick your commits and open a new PR with your changes.

• Please confirm you have the smaller repo (85MB .git directory vs 275MB or 110MB or 185MB .git directory)

Type of Change

• Bug fix (non-breaking change, fixes New-DbaDbSnapshot allows creating only one snapshot if database name contains a dot #8829 )
• New feature (non-breaking change, adds functionality, fixes # )
• Breaking change (affects multiple commands or functionality, fixes # )
• Ran manual Pester test and has passed (.\tests\manual.pester.ps1)
• Adding code coverage to existing functionality
• Pester test is included
• If new file reference added for test, has is been added to github.com/dataplat/appveyor-lab ?
• Unit test is included
• Documentation
• Build system

Purpose

Allow multiple snaps for db names with dot in it

Approach

Re-add extension to the filename before invoking changeextension.
Before "test.test_20230329_220615_0752_001" --> "test.ss"
Now "test.test_20230329_220615_0752_001.mdf" --> "test.test.20230329_220615_0752_001.ss"

Added a regression test to the test-suite.
And thanks to @itb-devs-de for reporting

[potatoqualitee]

Thank you for the tests 🙇🏼