Fix build warnings in MonoProxy (#18573)

Author: pranavkm

src/Components/Blazor/Server/src/MonoDebugProxy/ws-proxy/MonoProxy.cs

@@ -461,7 +461,7 @@ async Task GetDetails(int msg_id, int object_id, CancellationToken token, string
 				{
 					result = var_list
 				});
-			} catch (Exception e) {
+			} catch (Exception) {
 				Debug ($"failed to parse {res.Value}");
 			}
 			SendResponse(msg_id, Result.Ok(o), token);
@@ -534,7 +534,7 @@ async Task GetScopeProperties (int msg_id, int scope_id, CancellationToken token
 				});
 				SendResponse (msg_id, Result.Ok (o), token);
 			}
-			catch (Exception exc) {
+			catch (Exception) {
 				SendResponse (msg_id, res, token);
 			}
 		}