Remove '.' from HCS suffix

[Blue (OneBlue)]

Summary of the Pull Request

This change updates the HCS suffix filter to correctly remove '.' from the process suffix.

Sample failure:

λ wslc system session enter test-storage\ --name foo.bar
The parameter is incorrect.
Error code: E_INVALIDARG

PR Checklist

• Closes: Link to issue wslc all commands give E_INVALIDARG #40944
• Communication: I've discussed this with core contributors already. If work hasn't been agreed, this work might be rejected
• Tests: Added/updated if needed and all pass
• Localization: All end user facing strings can be localized
• Dev docs: Added/updated if needed
• Documentation updated: If checked, please file a pull request on our docs repo and link it here: #xxx

Detailed Description of the Pull Request / Additional comments

Validation Steps Performed

[Copilot]

Pull request overview

This PR fixes a Windows Host Compute Service (HCS) compatibility issue by tightening the character allowlist used when generating HostingProcessNameSuffix, ensuring . characters are replaced (sanitized) rather than passed through. This prevents E_INVALIDARG failures when the session/display name contains dots (e.g., foo.bar), which can otherwise break wslc session creation and cascade into widespread command failures.

Changes:

• Remove . from the allowlist used by SanitizeHostingProcessNameSuffix, causing dots to be converted to _ before being assigned to HostingProcessNameSuffix.