[FIX] hr,(_contract): fix small issue of groupby dropdown

Currently, groupby and filter dropdown are not working properly
on employee kanban card because when dropdown is exact on position of
fixed-bottom it will direcly click on the kanban card instead of the
custom groupby dropdown due to higher z-index of the fixed-bottom then
dropdown-menu. also chat icon in fixed-bottom is overlap on zoomed
image as zoomodoo-flyout has z-index 100.

fixed-bottom has z-index 1030 while drodown has z-index 1000 so instead
of clicking on dropdown it was going to click on kanbancard bottom.

So in this commit, improve the behaviour and decrease the z-index of
fixed-bottom to allow the click on custom groupby dropdown and hide
the chat icon behind the zoomed image.

Also when try to create contract, employee field does not show proper.
so moved it before start date with label.

closes odoo/odoo#66788

Taskid: 2452363
Signed-off-by: Yannick Tivisse (yti) <yti@odoo.com>

addons/hr/static/src/scss/hr.scss

@@ -19,4 +19,8 @@
         white-space: nowrap;
     }
 
+    .oe_kanban_content.fixed-bottom {
+        z-index: 100;
+    }
+
 }

addons/hr_contract/views/hr_contract_views.xml

@@ -143,12 +143,12 @@
                             </h1>
                             <h2>
                                 <field name="company_id" groups="base.group_multi_company" invisible="1"/>
-                                <field name="employee_id"/>
                             </h2>
                         </div>
                         <group name="top_info">
                             <group name="top_info_left">
                                 <field name="active" invisible="1"/>
+                                <field name="employee_id"/>
                                 <field name="date_start"/>
                                 <field name="date_end"/>
                                 <field name="company_country_id" invisible="1"/>