fix(VIcon): properly apply dense height to svg

[matthieusieben]

Description

The CSS generated to alter the dense property should look like this:

.v-icon--dense .v-icon__svg { ... }

It currently looks like this:

.v-icon--dense .v-icon--dense__svg { ... }

which fails to properly target the SVG (svg.v-icon__svg)

Motivation and Context

Currenly, the dense property of v-icon has no effect on the height of the element

How Has This Been Tested?

visually

Markup:

Details

// Paste your FULL Playground.vue here

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Improvement/refactoring (non-breaking change that doesn't add any features but makes things better)

Checklist:

• The PR title is no longer than 64 characters.
• The PR is submitted to the correct branch (master for bug fixes and documentation updates, dev for new features and backwards compatible changes and next for non-backwards compatible changes).
• My code follows the code style of this project.
• I've added relevant changes to the documentation (applies to new features and breaking changes in core library)