Error Undefined control sequence. \MFUexcl{\ensuremath} when running the sample code to create a list of symbols

Question

I'm running the following sample code from How to effectively use List of Symbols for a thesis?

\documentclass{report}
\usepackage{amsthm,xparse}
\ExplSyntaxOn
\usepackage[colorlinks]{hyperref}
\usepackage[symbols,nogroupskip,nonumberlist,sort=use]{glossaries-extra}
\usepackage{mfirstuc}
\usepackage{xkeyval}
\makenoidxglossaries

\glsxtrnewsymbol[description={position}]{x}{\ensuremath{x}}
\glsxtrnewsymbol[description={velocity}]{v}{\ensuremath{v}}
\glsxtrnewsymbol[description={acceleration}]{a}{\ensuremath{a}}
\glsxtrnewsymbol[description={time}]{t}{\ensuremath{t}}
\glsxtrnewsymbol[description={force}]{F}{\ensuremath{F}}

\begin{document}
    \tableofcontents
    \printnoidxglossary[type=symbols,style=long,title={List of Symbols}]
    
    \chapter{Sample}
    Reference symbols: $\gls{F}$, $\gls{t}$, $\gls{x}$, $\gls{v}$, $\gls{a}$.
    
\end{document}

And I receive the error "mfirstuc.sty Undefined control sequence. \MFUexcl{\ensuremath}"

I've tried installing all the packages I could see where missing but I'm just not getting it to compile. Please help