[MDC] Fix le_mdc_StartSessionAsync API
[MDC] Fix le_mdc_StartSessionAsync API

Add error code when le_mdc_StartSessionAsync() fails

Resolves: LE-9904
Change-Id: Icf349986cfee3d54085d8ad45c26dc4e7ca02f1e

legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af,legatoproject/legato-af