MidnightNameplates 0.10.2.2 - Import/Export Scroll Fix

ROOT CAUSE
- Phase 10.2.1 called EditBox:GetStringHeight().
- WoW EditBox does not provide GetStringHeight(), causing nil-call errors in both export and import boxes.

FIX
- Removed all EditBox:GetStringHeight() calls.
- Added a safe text-height estimator based on box width and text length.
- Export and Import edit boxes now resize their scroll child safely.
- Explicit initial edit-box heights added.
- Compact internal ScrollFrame design remains intact.
- Import/export string format is unchanged.

TEST
1. Open Profiles.
2. Generate FULL export.
3. No Lua error should occur.
4. Export string remains inside compact scroll box.
5. SELECT ALL + Ctrl+C.
6. Paste into Import box with Ctrl+V.
7. No Lua error should occur.
8. PREVIEW IMPORT and IMPORT still work.
9. Delete confirmation still works.
