Default blobstore on new NavAbilityDFG be same as fgLabel rather than :default

```julia
fg = NavAbilityDFG(auth_token, fglb, aglb; apiUrl, orgLabel=orlb, addAgentIfAbsent=false, addGraphIfAbsent=true)

# NavAbilityDFG{VariableDFG, FactorDFG}
#   FactorGraph: FG_9999
#   Agent: BOT_01
#   BlobStores: [:default]   <-- let this use a more unique location, e.g. FG_9999
```