Revert the trending words query to the old one + FINAL

[IvanIvanoff]

In the now reverted query there is a check like t = dt and t = last_dt_in_group. This is an issue because t is being computed as the beginning of the interval, so a check where t=last_dt_in_group would never yield the required result -- the data with last dt

Changes

Ticket

Checklist:

• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• I have tried to find clearer solution before commenting hard-to-understand parts of code
• I have added tests that prove my fix is effective or that my feature works