bug: [Python] write_deltalake does not enforce schema

[wjones127]

Environment

Delta-rs version: 0.5.7

Binding: Python

Environment:

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Bug

What happened:

What you expected to happen:

How to reproduce it:

See https://github.com/MrPowers/delta-examples/blob/8d08441ea2e6986fdd4ab0d7d03cca7d64968c99/notebooks/delta-rs/intro-to-delta-rs.ipynb

More details:

We should be enforcing the schema here, when we know the table already exists and we know the schema:

delta-rs/python/deltalake/writer.py

Lines 144 to 149 in 92c35d8

	if table: # already exists
	if mode == "error":
	raise AssertionError("DeltaTable already exists.")
	elif mode == "ignore":
	return