Remove mjData.qLDiagSqrtInv, add corresponding argument to mj_solveM2.

- `qLDiagSqrtInv` is only required for the dual solvers. It is now computed as-needed rather than unconditionally.
- `mj_solveM2` now requires a new input array `sqrtInvD` which contains the square root of the inverse diagonal D (formerly saved in `qLDiagSqrtInv`).

PiperOrigin-RevId: 710805133
Change-Id: I0622d6a8da3882916824e9c10bad9223c122c321

introspect/functions.py

@@ -1868,6 +1868,12 @@ FUNCTIONS: Mapping[str, FunctionDecl] = dict([
                      inner_type=ValueType(name='mjtNum', is_const=True),
                  ),
              ),
+             FunctionParameterDecl(
+                 name='sqrtInvD',
+                 type=PointerType(
+                     inner_type=ValueType(name='mjtNum', is_const=True),
+                 ),
+             ),
              FunctionParameterDecl(
                  name='n',
                  type=ValueType(name='int'),