fix: font styling and small ux bugs

[KristinAoki]

JIRA Ticket: TNL-11149

• Not enough spacing above and below heading
• Add space below alert component
• Fields should be spaced farther apart
• Error text should match Figma
• Remove “x” from error text
• Cancel and create buttons should be right aligned
• Fields and buttons should be inside of a card
• Menu should say “No results found” instead of “No options”

Before

After

[codecov[bot]]

Codecov Report

Attention: 4 lines in your changes are missing coverage. Please review.

Comparison is base (fbdc822) 52.39% compared to head (e41267a) 52.41%.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #373 +/- ## ========================================== + Coverage 52.39% 52.41% +0.02% ========================================== Files 75 75 Lines 1983 1986 +3 Branches 359 359 ========================================== + Hits 1039 1041 +2 - Misses 911 912 +1 Partials 33 33 ``` | [Files](https://app.codecov.io/gh/openedx/frontend-app-library-authoring/pull/373?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openedx) | Coverage Δ | | |---|---|---| | [src/library-authoring/common/FormGroup.jsx](https://app.codecov.io/gh/openedx/frontend-app-library-authoring/pull/373?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openedx#diff-c3JjL2xpYnJhcnktYXV0aG9yaW5nL2NvbW1vbi9Gb3JtR3JvdXAuanN4) | `94.11% <100.00%> (ø)` | | | [...ary-authoring/create-library/LibraryCreatePage.jsx](https://app.codecov.io/gh/openedx/frontend-app-library-authoring/pull/373?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openedx#diff-c3JjL2xpYnJhcnktYXV0aG9yaW5nL2NyZWF0ZS1saWJyYXJ5L0xpYnJhcnlDcmVhdGVQYWdlLmpzeA==) | `79.68% <100.00%> (+1.56%)` | :arrow_up: | | [src/library-authoring/create-library/messages.js](https://app.codecov.io/gh/openedx/frontend-app-library-authoring/pull/373?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openedx#diff-c3JjL2xpYnJhcnktYXV0aG9yaW5nL2NyZWF0ZS1saWJyYXJ5L21lc3NhZ2VzLmpz) | `100.00% <ø> (ø)` | | | [src/library-authoring/create-library/data/slice.js](https://app.codecov.io/gh/openedx/frontend-app-library-authoring/pull/373?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=openedx#diff-c3JjL2xpYnJhcnktYXV0aG9yaW5nL2NyZWF0ZS1saWJyYXJ5L2RhdGEvc2xpY2UuanM=) | `14.28% <0.00%> (-1.72%)` | :arrow_down: |

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