fix: UIKit block messages rendering with smaller font size (#7531)

* fix: UIKit block messages rendering with smaller font size

* fix: snapshot

Author: OtavioStasiak

app/containers/UIKit/UiKitMessage.stories.tsx

@@ -2,6 +2,7 @@ import { ScrollView, View } from 'react-native';
 import { type ReactElement } from 'react';
 
 import { UiKitMessage } from '.';
+import Markdown from '../markdown';
 import { colors } from '../../lib/constants/colors';
 import { longText } from '../../../.rnstorybook/utils';
 import {
@@ -54,6 +55,39 @@ export const SectionMarkdownList = () =>
 	]);
 SectionMarkdownList.storyName = 'Section + Markdown List';
 
+// App messages are rendered from blocks, so their mrkdwn goes through
+// MessageParser.mrkdwn instead of the regular message Markdown path. Both must
+// render at the same font size, otherwise app messages look smaller than the
+// user's messages in the same list.
+const appMessageText =
+	'Updating workspace from 8.7.0-rc.1 to 8.7.0-rc.2\n\t\tchanges: https://github.com/RocketChat/Rocket.Chat/compare/8.7.0-rc.1...8.7.0-rc.2\n\t';
+
+export const SectionFontSizeParity = () => (
+	<View>
+		<Markdown msg='Regular message: the reference font size' />
+		{UiKitMessage([
+			{
+				type: 'section',
+				text: {
+					type: 'mrkdwn',
+					text: 'Section mrkdwn: must match the message above'
+				}
+			}
+		])}
+		<Markdown msg={appMessageText} />
+		{UiKitMessage([
+			{
+				type: 'section',
+				text: {
+					type: 'mrkdwn',
+					text: appMessageText
+				}
+			}
+		])}
+	</View>
+);
+SectionFontSizeParity.storyName = 'Section + Message font size parity';
+
 export const SectionOverflow = () =>
 	UiKitMessage([
 		{