[FIX] web: fix width of 1st column on bold layout timesheet report

Current behaviour:
When having the `external_layout_bold` as Document layout,
when printing timesheets, the date column takes too much width
of the table.

Expected behaviour:
Have the columns be proportional, similar to the
`external_layout_standard` layout.

Steps to reproduce:
- Install Timesheet
- Activate Dev Mode
- Change the Document layout to `external_layout_bold`
- Timesheets > List View > Select an item > Print
- Observe that the first columns (with Date) is taking 1/2 of the width

Reason for the problem:
I presume some leftover legacy styling with a `width:48%` for the
first column of a bold_layout table.

Fix:
Remove that legacy styling.

Affected versions:
- 15.0
- saas-15.2
- saas-15.3
- 16.0
- master

opw-3114053

closes odoo/odoo#110723

X-original-commit: 01c0eb16b5c3d418e5a494a825cc60f76a743377
Signed-off-by: Aaron Bohy (aab) <aab@odoo.com>

addons/web/static/src/webclient/actions/reports/layout_assets/layout_clean.scss

@@ -40,9 +40,6 @@
                 border-top: 3px solid $o-default-report-secondary-color !important;
                 text-transform: uppercase;
             }
-            tr th:first-child {
-                width: 48%;
-            }
         }
         tbody {
             color: #000;