[Card] `CardContent` padding doesn't use spacing

Duplicates

• I have searched the existing issues

Latest version

• I have tested the latest version

Current behavior 😯

CardContentRoot defines padding—and padding-bottom for the last child—with hardcoded values, without using the spacing from the theme.

See https://github.com/mui/material-ui/blob/585c4a3850936d7ddcd60ed4ad063996415e0f3a/packages/mui-material/src/CardContent/CardContent.js#L25-L27.

Expected behavior 🤔

CardContentRoot defines padding—and padding-bottom for the last child—without hardcoded values, using the spacing from the theme.

Steps to reproduce 🕹

See https://github.com/mui/material-ui/blob/585c4a3850936d7ddcd60ed4ad063996415e0f3a/packages/mui-material/src/CardContent/CardContent.js#L25-L27.

Context 🔦

While using MUI, I was expecting that all paddings and margins set in the different components would respect the spacing set within the theme.

Your environment 🌎

I'm using Chrome and Safari.

System:
    OS: macOS 11.6.4
  Binaries:
    Node: 14.17.3 - ~/.nvm/versions/node/v14.17.3/bin/node
    Yarn: 1.22.11 - ~/.nvm/versions/node/v14.17.3/bin/yarn
    npm: 6.14.13 - ~/.nvm/versions/node/v14.17.3/bin/npm
  Browsers:
    Chrome: 100.0.4896.75
    Edge: Not Found
    Firefox: 67.0.2
    Safari: 15.1
  npmPackages:
    @emotion/react: ^11.7.1 => 11.7.1
    @emotion/styled: ^11.6.0 => 11.6.0
    @mui/base:  5.0.0-alpha.68
    @mui/icons-material: ^5.4.4 => 5.4.4
    @mui/material: ^5.4.1 => 5.4.1
    @mui/private-theming:  5.4.1
    @mui/styled-engine:  5.4.1
    @mui/system:  5.4.1
    @mui/types:  7.1.1
    @mui/utils:  5.4.1
    @types/react: ^17.0.24 => 17.0.39
    react: ^17.0.2 => 17.0.2
    react-dom: ^17.0.2 => 17.0.2
    typescript: ^4.1.2 => 4.5.5

Start in packages/mui-material/src/CardContent/CardContent.js at the referenced CardContentRoot definition. Compare its padding and last-child padding-bottom with the theme spacing API, then verify that both values respond to the configured theme spacing instead of remaining hardcoded. The issue does not name a test file, so inspect nearby CardContent tests for the appropriate place to cover the behavior.