Implemented trimming for item's name in Web IDE

Resolves https://gitlab.com/gitlab-org/gitlab-ce/issues/57540

app/assets/javascripts/ide/components/new_dropdown/modal.vue

@@ -29,7 +29,7 @@ export default {
         return this.name || (entryPath ? `${entryPath}/` : '');
       },
       set(val) {
-        this.name = val;
+        this.name = val.trim();
       },
     },
     modalTitle() {

changelogs/unreleased/57540-filename-trailing-space.yml

@@ -0,0 +1,5 @@
+---
+title: Implemented whitespace-trimming for file names in Web IDE
+merge_request: 26270
+author:
+type: fixed

spec/javascripts/ide/components/new_dropdown/modal_spec.js

@@ -109,6 +109,18 @@ describe('new file modal component', () => {
 
         expect(vm.entryName).toBe('index.js');
       });
+
+      it('removes leading/trailing spaces when found in the new name', () => {
+        vm.entryName = ' index.js ';
+
+        expect(vm.entryName).toBe('index.js');
+      });
+
+      it('does not remove internal spaces in the file name', () => {
+        vm.entryName = ' In Praise of Idleness.txt ';
+
+        expect(vm.entryName).toBe('In Praise of Idleness.txt');
+      });
     });
   });