Update connection string and fix VS build error. (Azure#34707)

Author: rajkumar-rangaraj

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/src/Internals/AzureMonitorTransmitter.cs

@@ -64,7 +64,7 @@ private static ConnectionVars InitializeConnectionVars(AzureMonitorExporterOptio
                 return ConnectionStringParser.GetValues(options.ConnectionString);
             }
 
-            throw new InvalidOperationException("A connection string was not found. This MUST be provided via either AzureMonitorExporterOptions or set in the environment variable 'APPLICATIONINSIGHTS_CONNECTION_STRING'");
+            throw new InvalidOperationException("A connection string was not found. Please set your connection string.");
         }
 
         private static ApplicationInsightsRestClient InitializeRestClient(AzureMonitorExporterOptions options, ConnectionVars connectionVars, TokenCredential? credential)

sdk/monitor/Azure.Monitor.OpenTelemetry.Exporter/src/Internals/ConnectionString/ConnectionStringParser.cs

@@ -44,7 +44,7 @@ public static ConnectionVars GetValues(string? connectionString)
             catch (Exception ex)
             {
                 AzureMonitorExporterEventSource.Log.WriteError("ConnectionStringError", ex);
-                throw new InvalidOperationException("Connection String Error: A valid connection string is required to send telemetry data to Azure Monitor. Please set your connection string.", ex);
+                throw new InvalidOperationException("Connection String Error: " + ex.Message, ex);
             }
         }
 

sdk/monitor/Azure.Monitor.OpenTelemetry/Azure.Monitor.OpenTelemetry.sln

@@ -20,6 +20,8 @@ Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Azure.Monitor.OpenTelemetry
 EndProject
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Azure.Monitor.OpenTelemetry.Tests", "tests\Azure.Monitor.OpenTelemetry.Tests\Azure.Monitor.OpenTelemetry.Tests.csproj", "{E047E7C5-F248-49DF-BC2C-A690BC5F0F71}"
 EndProject
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "Azure.Core.TestFramework", "..\..\core\Azure.Core.TestFramework\src\Azure.Core.TestFramework.csproj", "{3E77BE70-A052-44F1-9E79-CB6D266DB1B3}"
+EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
 		Debug|Any CPU = Debug|Any CPU
@@ -42,6 +44,10 @@ Global
 		{E047E7C5-F248-49DF-BC2C-A690BC5F0F71}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{E047E7C5-F248-49DF-BC2C-A690BC5F0F71}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{E047E7C5-F248-49DF-BC2C-A690BC5F0F71}.Release|Any CPU.Build.0 = Release|Any CPU
+		{3E77BE70-A052-44F1-9E79-CB6D266DB1B3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{3E77BE70-A052-44F1-9E79-CB6D266DB1B3}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{3E77BE70-A052-44F1-9E79-CB6D266DB1B3}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{3E77BE70-A052-44F1-9E79-CB6D266DB1B3}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE