[bugfix/frontend] restore blockquote “block” margin (#4465)

stripping `<blockquote>` of all the margin looks a bit funky. this only removes the inline margin. in English this generally means that it won’t have horizontal margin but will still have vertical margin.

Closes #4466

![before the change any content after the blockquote is flush against it without space](/attachments/7cc808ee-a999-435d-9235-60651a3d9bca)

![after the changes there is vertical rhythm](/attachments/3240480a-14ee-4739-a497-14237879993c)

## Checklist

Please put an x inside each checkbox to indicate that you've read and followed it: `[ ]` -> `[x]`

If this is a documentation change, only the first checkbox must be filled (you can delete the others if you want).

- [x] I/we have read the [GoToSocial contribution guidelines](https://codeberg.org/superseriousbusiness/gotosocial/src/branch/main/CONTRIBUTING.md).
- [ ] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
- [x] I/we have not leveraged AI to create the proposed changes.
- [x] I/we have performed a self-review of added code.
- [x] I/we have written code that is legible and maintainable by others.
- [ ] I/we have commented the added code, particularly in hard-to-understand areas.
- [ ] I/we have made any necessary changes to documentation.
- [ ] I/we have added tests that cover new code.
- [x] I/we have run tests and they pass locally with the changes. (I ran `go test ./...` from the main dir, they passed with one exception related to thumbnail file size, most likely caused by testing on macOS)
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4465
Co-authored-by: Zoë Bijl <code@moiety.me>
Co-committed-by: Zoë Bijl <code@moiety.me>

web/source/css/base.css

@@ -269,7 +269,7 @@ ol {
 blockquote {
 	padding: 0.5rem;
 	border-left: 0.2rem solid $border-accent;
-	margin: 0;
+	margin-inline: 0;
 	font-style: normal;
 
 	/*