Update example code for HealthChecks.CosmosDb

[marcelaction]

What this PR does / why we need it:

Wrong options class in the code example.

On line 24 in this file it mentions AzureCosmosDbHealthCheckOptions correctly for optionsFactory. But in the example code it uses the old CosmosDbHealthCheckOptions

Which issue(s) this PR fixes:

None

Special notes for your reviewer:

N/A

Does this PR introduce a user-facing change?:

No

Please make sure you've completed the relevant tasks for this PR, out of the following list:

• [x] Code compiles correctly
• [x] Created/updated tests
• [x] Unit tests passing
• [x] End-to-end tests passing
• [x] Extended the documentation
• [x] Provided sample for the feature

[marcelaction]

@dotnet-policy-service agree

[marcelaction]

Closing someone submitted the same PR 2 weeks ago