Bugs in loose leaf tea
It appears from another post that is indeed unusual to find foreign matter in loose leaf tea.  Is it normal to find something in tea?

That said, bugs in food are a fact of life.  Every food inspection agency has rules for how many bugs are allowed in different commodities. As a former grain inspector, I followed specific guidelines for how many bugs were allowed per lot. It isn't zero. 

I wouldn't consider the tea unsafe because of the worm unless you found live worms or many worms.  

Tea isn't listed, but you might find the USFDA list below informative.  It shows what rises to a level of concern for a number of foods.

https://www.fda.gov/food/ingredients-additives-gras-packaging-guidance-documents-regulatory-information/food-defect-levels-handbook#commodities