test: pin to extension versions when testing

[hallvictoria]

Description

Testing improvements / fixes:

• Pinning to extension versions while running tests. This ensures that we're running our tests using the latest extension versions, regardless of if it's a beta version or not.
• Adding EventGrid source Blob Trigger functions to the blob function app. While the functionality can't be tested here, we can ensure that these functions are being indexed properly.
• Skipping a dependency isolation test that fails when using artifact versions of the SDK / extensions

Fixes #

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