getExternalAuthRedirectUri doesn't add PKCE parameters to URL

[rahul1]

Description

When signing in to an external auth provider with PKCE, some identity providers require that the PKCE parameters code_challenge_method and code_challenge are set as URL parameters

• Okta
• Auth0

However, our getExternalAuthRedirectUriI() doesn't currently set those two params

medplum/packages/core/src/client.ts

Lines 1050 to 1063 in 83432e6

	getExternalAuthRedirectUri(
	authorizeUrl: string,
	clientId: string,
	redirectUri: string,
	loginRequest: BaseLoginRequest
	): string {
	const url = new URL(authorizeUrl);
	url.searchParams.set('response_type', 'code');
	url.searchParams.set('client_id', clientId);
	url.searchParams.set('redirect_uri', redirectUri);
	url.searchParams.set('scope', 'openid profile email');
	url.searchParams.set('state', JSON.stringify(loginRequest));
	return url.toString();
	}