fix: Multiple tracing bug fixes

This MR addresses the following bug fixes:

• Follow up about connection string parsing duplication and simplification
• Fix for when service name is not part of the connection string.
• OpenTelemetry rejects nil attributes. Removing them to avoid logging noise.
• Fix for buggy opentracing wrappers
• Making sure only one OTel provider is initialized
• Fix RequestInstrumenter propagation