chore: Update integration testing documentation

[kevjumba]

What this PR does / why we need it:

Which issue(s) this PR fixes:

Fixes #

[codecov-commenter]

Codecov Report

Merging #2983 (240a3c9) into master (2680f7b) will increase coverage by 0.02%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #2983      +/-   ##
==========================================
+ Coverage   77.82%   77.84%   +0.02%     
==========================================
  Files         192      194       +2     
  Lines       16427    16560     +133     
==========================================
+ Hits        12784    12891     +107     
- Misses       3643     3669      +26     

Flag	Coverage Δ
integrationtests	67.37% <ø> (-0.64%)	⬇️
unittests	59.85% <ø> (+0.78%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
sdk/python/feast/infra/utils/snowflake_utils.py	77.77% <0.00%> (-7.05%)	⬇️
sdk/python/feast/infra/online_stores/datastore.py	87.96% <0.00%> (-1.39%)	⬇️
...ocal_feast_tests/test_stream_feature_view_apply.py	97.95% <0.00%> (-0.66%)	⬇️
sdk/python/tests/utils/basic_read_write_test.py	100.00% <0.00%> (ø)
...python/tests/integration/e2e/test_universal_e2e.py	100.00% <0.00%> (ø)
...python/tests/unit/cli/test_cli_apply_duplicates.py	100.00% <0.00%> (ø)
...hon/tests/unit/local_feast_tests/test_e2e_local.py	100.00% <0.00%> (ø)
...nit/local_feast_tests/test_feature_service_read.py	100.00% <0.00%> (ø)
.../integration/online_store/test_online_retrieval.py
sdk/python/feast/infra/online_stores/snowflake.py	98.13% <0.00%> (ø)
... and 4 more

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[felixwang9817]

/lgtm

[feast-ci-bot]

[APPROVALNOTIFIER] This PR is APPROVED

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