While personally I think the current entry is fine, you can make these suggestions at the source (JMdict in this case). Jisho.org is mostly just a fancy UI and search engine to help comb through several different databases, not a place where that data itself is curated. All sources are listed in the footer and all entries also have direct links to the respective entry in the source database (when available). For example when you go to https://jisho.org/word/%E7%8F%BE%E9%87%91 you will find there is a direct link to https://www.edrdg.org/jmwsgi/edform.py?svc=jmdict&sid=&q=1263550&a=2 allowing you to make your change suggestion.
I agree with the above. I think you could add the "opportunistic" sense here, and maybe move the "self-interested" gloss to the top. But other than that I think the entry is fine in itself. E.g. the 実用日本語表現辞典 has 現金な as it's own entry with the gloss "言動を自分の利害や都合によって簡単に変更する態度などを示す表現。" roughly meaning "An expression showing an attitude of readily changing words and deeds according to one's own interests and circumstances". So if you feel like proposing the change on jmdict, go ahead.
Suggestion regarding "現金な"
Regarding the 2nd definition as displayed when searching for this word on this site:
Currently, the only translations given are "mercenary; self-interested; calculating". However, in many cases, I feel as if the phrase "現金なやつ" (or equivalent) could be more suitably translated into "opportunistic", as in one who easily changes their actions or views solely based on what is profitable or convenient.
On the contrary, the current definition of "mercenary" seems to only cater for a small portion of example sentences where the word 現金 (in this particular sense) can be found. It doesn't make sense to me that this translation would be the first in the list.
I suggest adding "opportunistic" as a translation and to change the suggestion order so that "mercenary" doesn't come on top of everything else.