fix unresolvable hidden_queries diff

[MisterSquishy]

when we added support for hidden_queries, we decided to omit the name of the outer query from state, and instead default it in using the value of the query-level hidden attribute. this neglected to account for the case when the user includes the name of the outer query in the map explicitly in HCL, which yields an unresolvable diff -- the provider thinks it needs to add the outer query name to state, but then refuses to actually add it on apply.

instead, as of this PR we will start tracking the outer query's hidden_queries entry in state (matching whatever the user has added in their HCL), and no longer default the value of the outer query's hidden state. the UI already uses the overall hidden value if the outer query's name is not specified in hidden_queries, so there's no need to set it explicitly here