Add ConsistencyLevel header to count guest users sample

[Copilot]

The "count the guest users in your organization" sample was missing the required ConsistencyLevel header needed for advanced query capabilities when using $count operations on Directory Objects.

This change adds the missing header to ensure consistency with other similar samples:

"headers": [
  {
    "name": "ConsistencyLevel",
    "value": "eventual"
  }
]

The sample now follows the same pattern as other $count operations like "count the users in your tenant excluding guests (raw count)" which already had this header. Both samples use /v1.0/users/$count with filters on user types and require the ConsistencyLevel header according to Microsoft Graph documentation for advanced query capabilities.

Fixes #174.

Warning

Firewall rules blocked me from connecting to one or more addresses (expand for details)

I tried to connect to the following addresses, but was blocked by firewall rules:

• docs.microsoft.com
  • Triggering command: node scripts/test-initiator.js --no-watch (dns block)
  • Triggering command: node scripts/test-initiator.js --no-watch --testNamePattern=count the guest users in your organization (dns block)
• learn.microsoft.com
  • Triggering command: node scripts/test-initiator.js --no-watch (dns block)

If you need me to access, download, or install something from one of these locations, you can either:

• Configure Actions setup steps to set up my environment, which run before the firewall is enabled
• Add the appropriate URLs or hosts to the custom allowlist in this repository's Copilot coding agent settings (admins only)

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[Copilot]

Pull Request Overview

This PR adds the required ConsistencyLevel header to the "count the guest users in your organization" sample query to enable advanced query capabilities for $count operations on Directory Objects.

• Adds missing ConsistencyLevel: eventual header to ensure compliance with Microsoft Graph requirements
• Aligns the sample with other similar $count operations that already include this header
• Fixes a functional issue where the query would not work properly without the required header

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