Fix project creation fail with attributes null values

src/components/Project/Edition/ProjectAttributeForm.vue

@@ -60,8 +60,8 @@ export default {
   },
 
   created() {
-    // Checks if the component is being used in the context of creating a new project.
-    if (this.$route.name === 'project_create') {
+    // Checks if the component is being used in the context of creating a new project and attribute's default value is set
+    if (this.$route.name === 'project_create' && this.attribute.default_value !== null) {
       // If so, initializes the attribute's value with its default value as defined in the attribute's settings.
       this.updateValue(this.attribute.default_value, this.attribute.id);
     }