Wording change: Remove arg type test for internal validation algorithm

The "validate buffer with descriptor given bufferView and descriptor"
was validating that the type of the buffer was MLBufferView. This is
not necessary, as all invokers (directly, and indirectly via "validate
graph resources") only accept MLBufferViews via the WebIDL signatures.

index.bs

@@ -1165,7 +1165,6 @@ partial interface MLContext {
     To <dfn>validate buffer with descriptor</dfn> given |bufferView| and |descriptor|, run the following steps:
   </summary>
   <div class=algorithm-steps>
-    1. If |bufferView| is not an {{MLBufferView}}, return false.
     1. If |bufferView|'s [=element type=] does not match to |descriptor|.{{MLOperandDescriptor/dataType}}  according to [this table](#appendices-mloperanddatatype-arraybufferview-compatibility), return false.
     1. If |bufferView|.\[[ByteLength]] is not equal to the [=byte length=] of |descriptor|, return false.
   </div>