Backport of #61541 to release/10.0-preview4

/cc @BrennanConroy @captainsafia

Update to Microsoft.OpenApi v2.0.0-preview.17

Description

Update the version of Microsoft.OpenApi we're using. We've been doing this fairly regularly throughout 10.0 as we inch towards the final 2.0 version of Microsoft.OpenApi. Helps us test out the latest features and bug bash quickly.

Customer Impact

Customers have been using the OpenApi previews a lot and so we want to be able to give them the latest and greatest ASAP to help identify issues.

Here is a quote from a customer about why we want this in preview4 instead of waiting for preview5:

It would be nice as there's a big dependency chain for stuff like Swashbuckle.AspNetCore where we can't use newer previews of Microsoft.OpenApi due to various binary-breaking changes along the way since p11, so without it we can't test anything newer until June (domaindrivendev/Swashbuckle.AspNetCore#3283 (comment))

Regression?

• Yes
• No

Risk

• High
• Medium
• Low

Good test coverage.

Verification

• Manual (required)
• Automated

Packaging changes reviewed?

• Yes
• No
• N/A