[FIX]Used bom.bom_line_ids instead of sbom.bom_line_ids,search boms on product ids of bom component,and browse record outside of if condition to, fix traceback when click on Recompute Price from Bom button in product variant form view

[FIX] Removed cost method field from product template form view to fix duplication of this field.

[REV] Revert changes for duplication of cost method bcoz it is fixed in master.