The "Citation" resource have no search parameters in FHIR R5

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**Describe the bug**
When getting [Citation](https://hl7.org/fhir/5.0.0-snapshot1/citation.html#resource) resource from the deployed or local running R5 fhir server, the common search parameters like "**_lastUpdated**" is not supported.

**FHIR Version?**
R5

**Data provider?**
CosmosDB

**To Reproduce**
Steps to reproduce the behavior:
1. Deploy or locally run a R5 fhir server.
2. Send the http request like
```https://localhost:44348/Citation?_lastUpdated=ge1970-01-01&_sort=_lastUpdated```

**Expected behavior**
The **Citation** resources.

**Actual behavior**
The fhir server response indicates that "**_lastUpdated**" is not supported, but this parameters is common basic search parameters according to fhir definition.
```Json
"issue": [
{
"severity": "warning",
"code": "not-supported",
"diagnostics": "The search parameter '_lastUpdated' is not supported for resource type 'Citation'."
},
{
"severity": "warning",
"code": "not-supported",
"diagnostics": "Sort parameter value '_lastUpdated' is invalid, must be a subset of valid search parameters for resource type 'Citation'."
}
]
```

**Other**
From the codes, seems ```VersionSpecificModelInfoProvider``` deliberately removed **Citation** from supported resources in [line 54](https://github.com/microsoft/fhir-server/blob/main/src/Microsoft.Health.Fhir.Shared.Core/VersionSpecificModelInfoProvider.cs#L54) when building search parameters definition for resources.

```CSharp
public IReadOnlyCollection GetResourceTypeNames()
{
List supportedResources = ModelInfo.SupportedResources;

if (Version == FhirSpecification.R5)
{
supportedResources = supportedResources.Where(x => x != "CanonicalResource" && x != "MetadataResource" && x != "Citation").ToList();
}

return supportedResources;
}
```

[AB#94600](https://microsofthealth.visualstudio.com/f8da5110-49b1-4e9f-9022-2f58b6124ff9/_workitems/edit/94600)

Start in src/Microsoft.Health.Fhir.Shared.Core/VersionSpecificModelInfoProvider.cs, especially GetResourceTypeNames and the R5 filtering shown in the issue. Reproduce the Citation request with _lastUpdated and _sort, then verify that Citation is included in the supported search-parameter definitions and both parameters are accepted.

Written by the indexing model from the issue text.