Functions run very slow when importing libraries [lang-Python]

imports of libraries such as numpy and pandas cause function to be very slow (20-30 seconds)

#### Repro steps

import pandas

#### Related information
python

Reproduce the report with the listed `import pandas` step and measure the stated 20–30 second delay. Then locate the Azure Functions host entry point that handles Python function startup and determine the expected import-time behavior; the issue names no file, test, or acceptance criterion, so confirm scope before changing code.

Written by the indexing model from the issue text.