Fix Body param name in ConnectorFunction

[LucGenetier]

We basically have a ConnectorFunction with a body param (IsBodyParameter == true), but the body name hint is not respected.

The operation contains the XMsBodyName extension, which should make it so that the body parameter is called item.
In practice however, the name ends up as dynamicProperties, which is incorrect, and therefore the call to the connector fails with 400.

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Quick analysis

we see the body name being retrieved at line 1444 and we'll use it properly at line 1514 when creating OpenApiParameter but it's not the case at line 1490...