You could take the negative values:

import plotly.graph_objects as go

fig = go.Figure(data=[go.Candlestick(x=df['Date_Time'],
                open=df['Open'],
                high=df['High'],
                low=df['Low'],
                close=df['Close'] )])
fig.show()

fig = go.Figure(data=[go.Candlestick(x=df['Date_Time'],
                open=-df['Open'],
                high=-df['High'],
                low=-df['Low'],
                close=-df['Close'] )])
fig.show()