Some stock patterns don't tile seamlessly

Summary:

Some of the stock patterns included in the pattern editor don't quite line up perfectly at tile boundaries.

Examples are

• Wave vertical lines shading
• Camouflage
• AP101

Here's a screenshot of the first one:

Steps to reproduce:

• Open Inkscape
• Draw a rectangle
• In the pattern editor, apply 'Wave vertical lines shading' to the rectangle

What happened?

Waves are jagged.

What should have happened?

Waves are smooth.

Version info

Inkscape 1.3-beta (aacce78c12, 2023-06-06)

    GLib version:     2.72.4
    GTK version:      3.24.33
    glibmm version:   2.66.2
    gtkmm version:    3.24.5
    libxml2 version:  2.9.13
    libxslt version:  1.1.34
    Cairo version:    1.16.0
    Pango version:    1.50.6
    HarfBuzz version: 2.7.4

    OS version:       Linux Mint 21.1