34726: sql: Fix panic when auto stats are computed on views r=andy-kimball a=andy-kimball

At startup, all crdb_internal.tables are enqueued in order to have stats
computed over them, if needed. However, that vtable includes views as well
as tables, and views cause the CREATE STATISTICS code to panic.

This commit fixes the panic (returns an error instead). It also prevents
the auto stats code from continually re-enqueuing the refresh request for
views and vtables, since they will fail every time.

We need to come back and fix this better by not enqueuing views in the
first place. However, that turned out to be problematic because the
crdb_internal.tables vtable has no column that distinguishes view from
tables.

Release note: None

Co-authored-by: Andrew Kimball <[email protected]>