Fix compilation warnings in dlz_sqlite3_dynamic.c

Fix compilation warnings in dlz_sqlite3_dynamic.c

    dlz_sqlite3_dynamic.c: In function ‘dlz_sqlite3_fetch_row’:
    dlz_sqlite3_dynamic.c:447:31: warning: comparison of integer expressions of different signedness: ‘int’ and ‘unsigned int’ [-Wsign-compare]
      447 |                 if (rs->pnRow > 0U && rs->curRow < rs->pnRow) {
          |                               ^
    dlz_sqlite3_dynamic.c:447:50: warning: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Wsign-compare]
      447 |                 if (rs->pnRow > 0U && rs->curRow < rs->pnRow) {
          |                                                  ^