Several realms textures use outdated textures (and show old generation)

(Reported here, rather than in REALMS project as the textures are included in the client jar file.)

The texture files which showcase the world selection options (adventure, experience, inspiration, survival spawn, new world and upload) use the old block and entity textures.

In case of the survival spawn option, it even showcases a pre-1.14 village, rather than a new village design.

There's an additional texture "empty_frame" which is a grayscale dirt texture, but it, too, is outdated.

Affected texture files:

• assets/realms/textures/gui/realms/adventure.png

• assets/realms/textures/gui/realms/empty_frame.png

• assets/realms/textures/gui/realms/experience.png

• assets/realms/textures/gui/realms/inspiration.png

• assets/realms/textures/gui/realms/new_world.png

• assets/realms/textures/gui/realms/survival_spawn.png

• assets/realms/textures/gui/realms/upload.png