Update app.py

Fixing a weird error called module not found, even though matplotlib should be installed as default, but I don't need it in my app anyway

app.py

@@ -12,7 +12,6 @@ import gradio as gr
 import pandas as pd
 import random
 import csv
-import matplotlib
 import plotly.graph_objects as go
 import matplotlib.pyplot as plt
 import simpy.resources