Increase orca retry timeout

[jonmmease]

As reported in plotly/orca#164, the current policy of retrying the first image export for up to 8 seconds is not always sufficient.

plotly.py/plotly/io/_orca.py

Lines 1194 to 1195 in a9fa5de

	@retrying.retry(wait_random_min=5, wait_random_max=10, stop_max_delay=8000)
	def request_image_with_retrying(**kwargs):

Lets increase this to 30 seconds to be on the safe side.

[jonmmease]

In the meantime, see workaround in plotly/orca#164 (comment)

[RylanSchaeffer]

I run into timeout issues when creating a scatter plot with 2^20 points. The following doesn't help:

plotly.io.orca.ensure_server()
time.sleep(10)

Any other suggestions?