docs(example-image-no-border): added styles for example image

[nikkimk]

What I did

1. Modified example SCSS for docs for an example image with no palette, or "none" as described in [feat] example image no border for docs #1023 .
2. Added "none" option in example shortcode documentation for palette.

Testing Instructions

1. Go to the first image under Sizes heading on Spinner's Guidelines page .
2. Image should have no padding.
3. Image should have no border.
4. Image should have no background.
5. Image should should be responsive.

Notes to Reviewers

Style should be similar what it currently looks like on ux.redhat.com but possibly less blurry.

[changeset-bot]

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Latest commit: 709b56e

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[github-actions]

Size Change: 0 B

Total Size: 187 kB

ℹ️ View Unchanged

Filename	Size
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./elements/rh-accordion/rh-accordion-panel.js	1.24 kB
./elements/rh-accordion/rh-accordion.js	1.15 kB
./elements/rh-alert/rh-alert.js	4.25 kB
./elements/rh-avatar/random-pattern-controller.js	2.72 kB
./elements/rh-avatar/rh-avatar.js	26.6 kB
./elements/rh-badge/rh-badge.js	745 B
./elements/rh-blockquote/rh-blockquote.js	1.96 kB
./elements/rh-button/rh-button.js	3.67 kB
./elements/rh-card/rh-card.js	1.96 kB
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./elements/rh-cta/rh-cta.js	3.76 kB
./elements/rh-dialog/rh-dialog.js	1.64 kB
./elements/rh-dialog/yt-api.js	614 B
./elements/rh-footer/rh-footer-block.js	765 B
./elements/rh-footer/rh-footer-copyright.js	362 B
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./elements/rh-footer/rh-footer-social-link.js	960 B
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./elements/rh-footer/rh-global-footer.js	250 B
./elements/rh-navigation-secondary/rh-navigation-secondary-dropdown.js	2.42 kB
./elements/rh-navigation-secondary/rh-navigation-secondary-menu-section.js	1.47 kB
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./elements/rh-navigation-secondary/rh-navigation-secondary-overlay.js	571 B
./elements/rh-navigation-secondary/rh-navigation-secondary.js	4.82 kB
./elements/rh-navigation-secondary/test/fixtures.js	851 B
./elements/rh-pagination/rh-pagination.js	4.17 kB
./elements/rh-spinner/rh-spinner.js	1.56 kB
./elements/rh-stat/rh-stat.js	2.3 kB
./elements/rh-subnav/rh-subnav.js	2.77 kB
./elements/rh-tabs/rh-tab-panel.js	697 B
./elements/rh-tabs/rh-tab.js	1.45 kB
./elements/rh-tabs/rh-tabs.js	1.61 kB
./elements/rh-tag/rh-tag.js	1.9 kB
./elements/rh-tooltip/rh-tooltip.js	1.14 kB
./lib/context/color/consumer.js	1.15 kB
./lib/context/color/controller.js	1.11 kB
./lib/context/color/provider.js	2 kB
./lib/context/event.js	598 B
./lib/DirController.js	488 B
./lib/functions.js	175 B
./lib/ScreenSizeController.js	856 B
./rhds.min.js	85.4 kB

_{compressed-size-action}

[zeroedin]

LGTM