fix: find auth_endpoint from OpenIDIssuer for aad

[LongOddCode]

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[Copilot]

Pull Request Overview

This PR updates the Azure Active Directory (AAD) authentication flow to dynamically discover the authorization endpoint using OpenID Connect metadata instead of hardcoding it. This ensures compatibility with different AAD tenant configurations that may have varying endpoint URLs.

• Introduces a new OpenIdHelper class to handle OpenID Connect discovery
• Updates AAD authentication to use discovered authorization endpoint
• Adds the openid-client dependency for OpenID Connect operations

Reviewed Changes

Copilot reviewed 3 out of 4 changed files in this pull request and generated 3 comments.

File	Description
src/msha/auth/routes/auth-login-provider-custom.ts	Updates AAD case to use dynamically discovered authorization endpoint
src/core/utils/openidHelper.ts	New utility class for OpenID Connect discovery operations
package.json	Adds openid-client dependency and reorders name/version fields

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