[bugfix] prevent clicking Enter in description field from deleting the image (#4436)

# Description

Change the type of "Delete header" / "Delete avatar" button to just "button" to prevent them from getting deleted if user presses Enter in the description field.

Closes https://codeberg.org/superseriousbusiness/gotosocial/issues/4363

## 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.
- [x] I/we have made any necessary changes to documentation.
- [ ] I/we have added tests that cover new code.
- [ ] I/we have run tests and they pass locally with the changes.
- [x] I/we have run `go fmt ./...` and `golangci-lint run`.

Co-authored-by: ptrcnull <git@ptrcnull.me>
Reviewed-on: https://codeberg.org/superseriousbusiness/gotosocial/pulls/4436
Co-authored-by: ptrcnull <ptrcnull@noreply.codeberg.org>
Co-committed-by: ptrcnull <ptrcnull@noreply.codeberg.org>

web/source/settings/components/form/mutation-button.tsx

@@ -27,6 +27,7 @@ export interface MutationButtonProps extends React.DetailedHTMLProps<React.Butto
 	showError?: boolean,
 	className?: string,
 	wrapperClassName?: string,
+	submit?: boolean,
 }
 
 export default function MutationButton({
@@ -36,6 +37,7 @@ export default function MutationButton({
 	showError = true,
 	className = "",
 	wrapperClassName = "",
+	submit = true,
 	...inputProps
 }: MutationButtonProps) {
 	let iconClass = "";
@@ -56,7 +58,7 @@ export default function MutationButton({
 				<Error error={result.error} reset={result.reset} />
 			}
 			<button
-				type="submit"
+				type={submit ? "submit" : "button"}
 				className={"with-icon " + className}
 				disabled={result.isLoading || disabled}
 				{...inputProps}

web/source/settings/views/user/profile/profile.tsx

@@ -184,6 +184,7 @@ function ProfileForm({ data: profile }: ProfileFormProps) {
 						tabIndex={0}
 						disabled={noHeader}
 						result={deleteHeaderRes}
+						submit={false}
 						onClick={(e) => {
 							e.preventDefault();
 							deleteHeader().then(res => {
@@ -215,6 +216,7 @@ function ProfileForm({ data: profile }: ProfileFormProps) {
 						tabIndex={0}
 						disabled={noAvatar}
 						result={deleteAvatarRes}
+						submit={false}
 						onClick={(e) => {
 							e.preventDefault();
 							deleteAvatar().then(res => {