Fix AmbiguousMatchException in ClearPool with FirebirdClient 6.6.0 and above (nhibernate#2758)

Author: hazzik

src/NHibernate.Test/NHibernate.Test.csproj

@@ -63,7 +63,7 @@
     <PackageReference Include="NUnit" Version="3.13.2" />
     <PackageReference Include="NUnit3TestAdapter" Version="3.15.1" />
     <PackageReference Include="Microsoft.NET.Test.Sdk" Version="16.9.4" />
-    <PackageReference Include="FirebirdSql.Data.FirebirdClient" Version="6.3.0" />
+    <PackageReference Include="FirebirdSql.Data.FirebirdClient" Version="6.6.0" />
     <PackageReference Include="Npgsql" Version="4.0.3" />
     <PackageReference Include="MySql.Data" Version="8.0.22" />
   </ItemGroup>

src/NHibernate/Driver/FirebirdClientDriver.cs

@@ -160,8 +160,8 @@ public void ClearPool(string connectionString)
 				using (var clearConnection = CreateConnection())
 				{
 					var connectionType = clearConnection.GetType();
-					_clearPool = connectionType.GetMethod("ClearPool") ?? throw new InvalidOperationException("Unable to resolve ClearPool method.");
-					_clearAllPools = connectionType.GetMethod("ClearAllPools") ?? throw new InvalidOperationException("Unable to resolve ClearAllPools method.");
+					_clearPool = connectionType.GetMethod("ClearPool", new[] { connectionType }) ?? throw new InvalidOperationException("Unable to resolve ClearPool method.");
+					_clearAllPools = connectionType.GetMethod("ClearAllPools", Array.Empty<System.Type>()) ?? throw new InvalidOperationException("Unable to resolve ClearAllPools method.");
 				}
 			}