files - implement isReadonly on model if provided

src/vs/workbench/common/editor.ts

@@ -672,9 +672,7 @@ export abstract class TextResourceEditorInput extends EditorInput {
 			return true; // resources without file support are always readonly
 		}
 
-		const model = this.textFileService.files.get(this.resource);
-
-		return model?.isReadonly() || this.fileService.hasCapability(this.resource, FileSystemProviderCapabilities.Readonly);
+		return this.fileService.hasCapability(this.resource, FileSystemProviderCapabilities.Readonly);
 	}
 
 	isSaving(): boolean {

src/vs/workbench/contrib/files/common/editors/fileEditorInput.ts

@@ -182,6 +182,14 @@ export class FileEditorInput extends TextResourceEditorInput implements IFileEdi
 		return !!(this.model?.isDirty());
 	}
 
+	isReadonly(): boolean {
+		if (this.model) {
+			return this.model.isReadonly();
+		}
+
+		return super.isReadonly();
+	}
+
 	isSaving(): boolean {
 		if (this.model?.hasState(ModelState.SAVED) || this.model?.hasState(ModelState.CONFLICT) || this.model?.hasState(ModelState.ERROR)) {
 			return false; // require the model to be dirty and not in conflict or error state