Validate url to prevent XSS attacks

[AnnMarieW]

This was reported in the Dash repo a few days ago, and the same vulnerability is in dmc as well.

For more info, please see: plotly/dash#2729

from dash import Dash, html
import dash_mantine_components as dmc

app=Dash(__name__)

app.layout = html.Div(
    dmc.NavLink(label="dmc link", href='javascript:alert(1)')
)

if __name__ == '__main__':
    app.run_server(debug=True)