[js/webgpu] set query type in onRunStart (#19202)
### Description
<!-- Describe your changes. -->
`env.webgpu.profiling` is a global flag. It may change before each
session.run. So the best place is to update it in `onRunStart` event.
After this, we can directly check `this.queryType`'s value. Without this
pr, we need to make sure that `getCommandEncoder()` is called before
checking `this.queryType`. Otherwise, it may happen that
`pendingKernels`'s length is not equal to `pendingDispatchNumber`'s
length. See the two ugly workarounds
[1)](https://github.com/microsoft/onnxruntime/pull/18989/commits/e630dbf528fc3a955702cceb968930d0abdfc652#diff-006fc84d3997f96a29b8033bd2075d6a0a9509211bd5812a6b934fc74fedfd9dR267-R268)
and
[2)](https://github.com/microsoft/onnxruntime/pull/18989/commits/e630dbf528fc3a955702cceb968930d0abdfc652#diff-618fe297fbe7a1da586380163b8fd2627311ccc217640a3c5cdc9c17a33472c1R73-R80)
if we don't introduce `onRunStart`. Or we need to call `setQueryType` in
each kernel run.
