Nested Math in Non-Default Text Fix (#1111)

* Fixing nested math in non-default text. Added appropriate screenshot tests.

* Adding appropriate logic for buildMathML and resolving tests.

* Addressing Kevin's comment. Adding tests.

* Adding appropriate screenshots.

* Removing unnecessary data, adding consistent naming convention.

* Cleanup

* Handling possible edge cases.

* Updating per PR comments

test/screenshotter/ss_data.yaml

@@ -309,7 +309,13 @@ TextStacked:
       \textsf{\textrm{\textbf{abc123}} \textbf{abc123} \textit{abc123}}\\
       \textit{abc123 \textbf{abc123} \textsf{abc123}}\\
   \end{matrix}
-TextWithMath: \text{for $a < b$ and $ c < d $}.
+TextWithMath: 
+  \begin{matrix}
+      \text{for $a < b$ and $ c < d $}. \\
+      \textsf{for $a < b$ and $ c < d $}. \\
+      \textsf{for $a < b \textbf{ and } c < d $} \\
+      \text{\sf for $a < b$ and $c < d$.}
+  \end{matrix}
 Unicode: \begin{matrix}\text{ÀàÇçÉéÏïÖöÛû} \\ \text{БГДЖЗЙЛФЦШЫЮЯ} \\ \text{여보세요} \\ \text{私はバナナです} \end{matrix}
 Units: |
     \begin{array}{ll}