add option to disable link sharing (#27626)

* add option to remove link-sharing from backend

* restrict make link-sharing in the frontend based on capability

* extend e2e project-sharing tests to cover OVERLEAF_DISABLE_LINK_SHARING=true

* throw an error when link sharing is disabled in TokenAccessHandler

* throw errors when attempting to add users to projects with link sharing disabled

* Update server-ce/test/project-sharing.spec.ts

Co-authored-by: Jakob Ackermann <jakob.ackermann@overleaf.com>

* add tests for existing access when link sharing is disabled

* update tests to specify access restrictions for read-only and read-write link shared projects

* [web] block access to legacy public project with link-sharing disabled

---------

Co-authored-by: Jakob Ackermann <jakob.ackermann@overleaf.com>
GitOrigin-RevId: 5f194dbcb790e973e427c58a3a4a738a5dd74cb4

services/web/test/unit/src/Authorization/AuthorizationManagerTests.js

@@ -63,6 +63,7 @@ describe('AuthorizationManager', function () {
       passwordStrengthOptions: {},
       adminPrivilegeAvailable: true,
       adminRolesEnabled: false,
+      moduleImportSequence: [],
     }
     this.AuthorizationManager = SandboxedModule.require(modulePath, {
       requires: {
@@ -448,6 +449,28 @@ describe('AuthorizationManager', function () {
           expect(this.result).to.equal('readAndWrite')
         })
       })
+
+      describe('with link-sharing disabled', function () {
+        beforeEach(async function () {
+          this.settings.disableLinkSharing = true
+          this.result =
+            await this.AuthorizationManager.promises.getPrivilegeLevelForProject(
+              null,
+              this.project._id,
+              this.token
+            )
+        })
+
+        it('should not call CollaboratorsGetter.getProjectAccess', function () {
+          this.CollaboratorsGetter.promises.getProjectAccess.called.should.equal(
+            false
+          )
+        })
+
+        it('should return false', function () {
+          expect(this.result).to.equal(false)
+        })
+      })
     })
 
     describe("when the project doesn't exist", function () {