[magnesj]

Improves stability when importing malformed or corrupted input files. Such files are now rejected or skipped instead of crashing or reading/writing outside allocated memory.

• GRDECL import: reject grids when keyword sizes do not match SPECGRID (null grid was dereferenced), and SPECGRID with fewer than three values.
• Perforation interval import: skip records with too few fields.
• VTK/VTU import: reject connectivity indices outside the vertex array (surface importer and RifVtkReader).
• Dual porosity: skip the unpaired last PORV value for odd value counts.
• ROFF: update roffcpp submodule to validate array lengths and token counts (Validate array lengths and token counts when parsing ROFF files (GHSA… CeetronSolutions/roffcpp#29).

Each fix has a regression test.

Fixes #14895.