fix: improve ui of out-of-stock products on the cart page

[SGrueber]

PR Type

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no API changes)
[ ] Build-related changes
[ ] CI-related changes
[ ] Documentation content changes
[ ] Application / infrastructure changes
[ ] Other:

What Is the Current Behavior?

If the user adds a product to cart and the product gets undeliverable, an error section is displayed.
The messages and the item description in the table are center-aligned.
The product name in the table is bold.

Issue Number: Closes #438

What Is the New Behavior?

The messages and the item description in table are left-aligned.
The product name in the table is not bold.

Does this PR Introduce a Breaking Change?

[ ] Yes
[x] No

Other Information

[iwiederhold]

The bug was fixed. Fine.
The distance between message and basket image is too large now. The user can't see the "CONTINUE SHOPPING" button.
Improvment:
.empty-cart .empty-cart-icon {
padding: 55px 0 30px;
}

padding 105px --> 55px

[SGrueber]

It depends on the user's screen size whether he can see the continue shopping button.
Nevertheless I changed the empty-cart-icon top padding from 105 to 60 ( 4 * spaceDefault)