Ahahaha I did way too much tea research, and whether it was plausible, or likely, for Jason - or Talia to drink this tea.
So now I'm going to tell you why I picked it.
Chai noomi basra is made from dried limes native to the Arab states of the Persian Gulf and Iraq (according to Wikipedia).
Ra's al Ghul was apparently born to a tribe of desert nomads in Arabia - in the Persian Gulf. It is therefore plausible that Ra's al Ghul drank it, and liked it.
The next bit isn't super relevant, but ehh, whatever.
From Arabia, he could detour through Persia and eventually, move over to Nanda Parbat - or the real world mountain of Nanga Parbat, the westernmost major peak of the Himalayas, in Pakistan.
Ra's keeps the Arabic, and the tea, from where he grew up. As such, the League speaks it, as does his family.
Though theoretically, Ra's' base - the one seen in Under the Hood, and Lost Days - and man I did so much pointless research for this - could theoretically be an island in the Red Sea, off the west coast of Yemen (which borders Saudi Arabia!) - and in summer, with the currents flowing south, Jason could, super theoretically, have ended up 126 miles south (he swam to shore, in the comics, where a motorbike was waiting for him, 126 miles south), in Djibouti - which has French as an official language. (Explaining the Hotel des 2 Lion that Jason stays at)
(Therefore explaining the tea, and the Arabic, quite nicely).
If he wasn't there, then I don't actually know where the heck he was. I don't think the writers were thinking about it too hard. (Not to mention that sometimes the headquarters of the LOA is in the Himalayas, sometimes it's in probably the Middle East, and sometimes it's in specifically Istanbul. The writers are just NOT consistent.)