fix(organizations): keep the get(id, callback) overload alongside testmode

Adding `testmode` through the usual params-only overload pair dropped the
released `get(id, callback)` signature, turning that call into a TS2559
compile error and leaving the binder internally inconsistent (getCurrent
and getPartnerStatus still accept a bare callback). Restore it with a
four-overload form so both `get(id, callback)` and `get(id, params,
callback)` type-check.

Also cover OrganizationHelper.getDashboardUrl() for both the populated
link and the null-when-absent case, matching the payments and orders
helper tests.

Author: janpaepke

src/binders/organizations/OrganizationsBinder.ts

@@ -22,12 +22,16 @@ export default class OrganizationsBinder extends Binder<OrganizationData, Organi
    * @since 3.2.0
    * @see https://docs.mollie.com/reference/get-organization
    */
-  public get(id: string, parameters?: GetParameters): Promise<Organization>;
+  // Four overloads (rather than the params-only pair used by other binders) so the released
+  // `get(id, callback)` signature keeps compiling while `testmode` is also accepted.
+  public get(id: string): Promise<Organization>;
+  public get(id: string, callback: Callback<Organization>): void;
+  public get(id: string, parameters: GetParameters): Promise<Organization>;
   public get(id: string, parameters: GetParameters, callback: Callback<Organization>): void;
-  public get(id: string, parameters?: GetParameters) {
+  public get(id: string, parameters?: GetParameters | Callback<Organization>) {
     if (renege(this, this.get, ...arguments)) return;
     assertWellFormedId(id, 'organization');
-    return this.networkClient.get<OrganizationData, Organization>(`${pathSegment}/${id}`, parameters);
+    return this.networkClient.get<OrganizationData, Organization>(`${pathSegment}/${id}`, parameters as GetParameters | undefined);
   }
 
   /**

tests/unit/resources/organizations.test.ts

@@ -23,6 +23,10 @@ const response = {
       href: 'https://docs.mollie.com/reference/v2/organizations-api/get-organization',
       type: 'text/html',
     },
+    dashboard: {
+      href: 'https://www.mollie.com/dashboard/org_12345678',
+      type: 'text/html',
+    },
   },
 };
 
@@ -47,6 +51,7 @@ function testOrganization(organization) {
     href: 'https://docs.mollie.com/reference/v2/organizations-api/get-organization',
     type: 'text/html',
   });
+  expect(organization.getDashboardUrl()).toBe('https://www.mollie.com/dashboard/org_12345678');
 }
 
 test('getOrganization', () => {
@@ -69,6 +74,20 @@ test('getCurrentOrganization', () => {
   });
 });
 
+test('getDashboardUrl returns null when the organization has no dashboard link', () => {
+  return new NetworkMocker(getApiKeyClientProvider()).use(async ([mollieClient, networkMocker]) => {
+    const responseWithoutDashboard = {
+      ...response,
+      _links: { self: response._links.self, documentation: response._links.documentation },
+    };
+    networkMocker.intercept('GET', '/organizations/org_12345678', 200, responseWithoutDashboard).twice();
+
+    const organization = await bluster(mollieClient.organizations.get.bind(mollieClient.organizations))('org_12345678');
+
+    expect(organization.getDashboardUrl()).toBeNull();
+  });
+});
+
 test('getPartnerStatus', () => {
   const partnerStatusResponse = {
     resource: 'partner',