`--nv-tip-width` should use pseudo-element

[mrleblanc101]

--nv-tip-width should use a pseudo-element instead of a box-shadow to prevent it being affected by border-radius.

Before:

After:

.Notivue__notification {
    overflow: hidden;
    &::before {
        content: "";
        display: block;
        border-left: var(--nv-tip-width) solid var(--nv-accent);
        align-self: stretch;
    }
}

[smastrom]

Hi @mrleblanc101, thank you for the heads up. The improvement will be included in the next release.