convertLatexToMathMl generates invalid MathML superscript structure

[LinhTT46]

Description

The convertLatexToMathMl feature converts superscript expressions like x^2, y^2, n^2 ... without <mi> tag

Steps to Reproduce

MathLive.convertLatexToMathMl('x^2')

output: <msup>x<mn>2</mn></msup>

Expected Behavior

Grab x in <mi> tag
<msup><mi>x</mi><mn>2</mn></msup>

I already test this bug in version 0.89 and the latest version 0.91.2, it still occurs in both versions. Currently, I'm using version 0.89 so please fix this bug from that version. Thank you so much.

Environment

MathLive version: 0.89, ..., 0.91.2

Operating System Ubuntu 20.04.5

Browser Chrome

[LinhTT46]

I just found the similar issue here 1870