Additional validation for assay run configurations

[labkey-klum]

Rationale

related issue

This change validates the shape of the run properties that might be passed into the experiment.createRun function so we don't fail when we try to parse the JSON posted data on the server. The repro is to run this or similar code:

runConfig <- fromJSON(txt='{"name" : "api imported run",
    "properties" : ["lab" , "test lab", "location" , "Seattle"]
    }')

run <- labkey.experiment.createRun(runConfig, dataRows = df)

The other client APIs don't seem to have this problem due to the presence of more composed types versus allowing free form JSON text.

With this change, if the properties object is not valid, we will throw the following error (list is the R data type that serializes to a JSON object):

[cnathe]

minor: the first param is "config" so should this say "config properties must be a list of key value pairs."?