[FIX] base: allow admin to modify paperformats

If a user creates a paperformat, he should be able to modify it too.
Employees have no reason to modify the paperformat though (nor create).
Having a malicious employee modifying an existing report may be dangerous.

[CLA] signature for stijnh92

Fixes #26292

closes odoo/odoo#27444

doc/cla/individual/stijnh92.md

+Belgium, 2018-09-05
+
+I hereby agree to the terms of the Odoo Individual Contributor License
+Agreement v1.0.
+
+I declare that I am authorized and able to make this agreement and sign this
+declaration.
+
+Signed,
+
+Stijn Houben stijnhouben92@gmail.com https://github.com/stijnh92

odoo/addons/base/security/ir.model.access.csv

@@ -97,4 +97,4 @@
 "access_ir_actions_client","ir_actions_client all","model_ir_actions_client",,1,0,0,0
 "access_ir_logging","ir_logging admin","model_ir_logging","group_erp_manager",1,1,1,1
 "paperformat_access_portal","ir_actions_report_paperformat group_portal","model_report_paperformat",,1,0,0,0
-"paperformat_access_employee","ir_actions_report_paperformat group_hr_user","model_report_paperformat",,1,0,1,0
+"paperformat_access_employee","ir_actions_report_paperformat group_system","model_report_paperformat",group_system,1,1,1,1