Fix wrong path pattern describing sprite files

Purpose

For submitting jh only svg files, JH is going to create sub folder jh in illustrations and sprite_icons folders in the forking repo(https://jihulab.com/gitlab-cn/gitlab-svgs/), however, a wrong path pattern describing sprite files will make the compile of icon sprite fail, this MR is to fix it.

before:

/sprite_icons**/*/svg

after:

/sprite_icons/**/*/svg

Screenshots

Checklist

For a new icon and/or illustration:

• Link to related design issue:
• If this adds an icon ensure that it follows the new icon checklists.
• If this adds an illustration ensure that it follows the new illustration checklists.

For third-party trademarks:

• If this adds or updates an icon or illustration that includes a third-party trademark, ensure that it follows the process for adding third-party trademarks to GitLab.

/cc @daveliu