a11y: add missing alt attribute for decorative images

[aalves08]

Setup

• Rancher version:
• Rancher UI Extensions:
• Browser type & version:

Describe the bug

a11y issue 88
The "alt" attribute is not provided in the source code of the decorative image that resulted in screen reader users accessing the decorative image and communicated as unlabelled.

Account and API Keys
Main Content

• Decorative image in "Account" section

Create Project
Main content

• Decorative image in "Members" section

Extensions
Main content

• Decorative images associated with "AKS Provisioning", "EKS Provisioning" and so on text.

To Reproduce

Result
The "alt" attribute is not provided in the source code of the decorative image that resulted in screen reader users accessing the decorative image and communicated as unlabelled.

Expected Result

Decorative image should be hidden from screen readers OR provide a meaningful alt attribute

Screenshots

Additional context

[izaac]

Rancher version: v2.12-71a527a9c07db8bcc2ddfe95ae3ed5bd012f4589-head
UI version: master 980d4b0

Firefox version: 138
Chrome version: 136

I wasn't able to navigate with ordinary methods using the keyboard to the decorative images. Using on the other hand dev tools to force their selection I was able to capture the voice over. However with the alt text attribute on these images is good enough to meet the acceptance criteria. ✅