Fixes the ability to set arbitrary project rate

[crsib]

Resolves: #4612

• I signed CLA
• The title of the pull request describes an issue it addresses
• If changes are extensive, then there is a sequence of easily reviewable commits
• Each commit's message describes its purpose and effects
• There are no behavior changes unnecessary for the stated purpose of the PR

Recommended:

• Each commit compiles and runs on my machine without known undesirable changes of behavior

[petersampsonaudacity]

Testing on W10 with @crsib 's branch build: audacity-win-3.3.1-alpha-20230426+7b5ab99-x64

This looks to be properly fixed in this branch build - I can now set both the Project Sample Rate and the Default Sample Rate to arbitrary values using the "other" settings.