fix(mcp): scope mcp and sort order settings to application VSCODE-800

[ivandevp]

Description

Sets an explicit scope on several mdb.mcp.* settings and mdb.defaultSortOrder so they're only read from user settings, matching mdb.mcp.readOnly. mdb.mcp.exportsPath is scoped to machine.

Checklist

• New tests and/or benchmarks are included
• Documentation is changed or added
• I have signed the MongoDB Contributor License Agreement (https://www.mongodb.com/legal/contributor-agreement)

Motivation and Context

Fixes VSCODE-800.

• Bugfix
• New feature
• Dependency update
• Misc

Types of changes

• Backport Needed
• Patch (non-breaking change which fixes an issue)
• Minor (non-breaking change which adds functionality)
• Major (fix or feature that would cause existing functionality to change)