[FIX] base: company_id on res.partner associated to company

The fact that there is a company id set means that you cannot select the
partner in a M2o if you didn't select the company in the selector, and
that you cannot open a document where that partner is set if you are not
in the correct company.
This is an issue for inter_company_rules, as you should be able to
select the company to make a so, po or invoice to a company of the same
database.

odoo/addons/base/data/res_company_data.xml

@@ -17,9 +17,5 @@
             <field name="type">binary</field>
             <field name="url">/web/static/src/scss/report_styles.scss</field>
         </record>
-
-        <record id="main_partner" model="res.partner">
-            <field name="company_id" ref="main_company"/>
-        </record>
-    </data> 
+    </data>
 </odoo>