[Docs] Add sbhelper note to sbtrace target tool
[Docs] Add sbhelper note to sbtrace target tool

Add info that sbhelper usually runs sbtrace
and still need requires section

Resolves: LE-5801
Change-Id: Ic9e7253a335616eab7ba6962737a6f9fbedbc9bc

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