Fix CS1591: Add XML documentation to GetDummyQuery method

[Copilot]

Checklist

• I have read the Contributing Guide
• I have checked to ensure this does not introduce an unintended breaking changes
• I have considered appropriate testing for my change

Description

CS1591 build failure due to missing XML documentation on protected override method.

Change:
Added <summary> tag to OracleConnectionManager.GetDummyQuery():

/// <summary>
/// Gets a dummy query used to test the connection.
/// </summary>
protected override string GetDummyQuery() => "select 1 from dual";

Build now succeeds with GenerateDocumentationFile enabled.

Original prompt

Add a missing XML documentation comment to the GetDummyQuery method in OracleConnectionManager.cs to fix CS1591 build error.

Replace:
protected override string GetDummyQuery() => "select 1 from dual";

With:
///

/// Returns a simple dummy query for Oracle.
///

protected override string GetDummyQuery() => "select 1 from dual";

This ensures compliance with documentation requirements for publicly visible members.

This pull request was created from Copilot chat.

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[droyad]

Previous PR was missing this. Since it was old, I couldn't figure out how to run the CI.