[MM-63455] Fix Link previews with brackets when making the request (#30507)

* allow opening angle bracket before links

* cut off link before an angle bracket(both open & close)

* add more test cases for ParseURLAutolink func

* add more test cases for ParseWWWAutolink func

* add more test cases for TrimTrailingCharactersFromLink func

* add more test cases for GetFirstLinkAndImages func

* add test cases for isAllowedBeforeWWWLink func

* allow closing angle bracket and opening paranthesis before links

---------

Co-authored-by: Mattermost Build <build@mattermost.com>

server/public/shared/markdown/autolink.go

@@ -58,7 +58,7 @@ func parseWWWAutolink(data string, position int) (Range, bool) {
 
 func isAllowedBeforeWWWLink(c byte) bool {
 	switch c {
-	case '*', '_', '~', ')':
+	case '*', '_', '~', ')', '<', '(', '>':
 		return true
 	}
 	return false
@@ -174,9 +174,9 @@ func trimTrailingCharactersFromLink(markdown string, start int, end int) int {
 	runes := []rune(markdown[start:end])
 	linkEnd := len(runes)
 
-	// Cut off the link before an open angle bracket if it contains one
+	// Cut off the link before an angle bracket if it contains one
 	for i, c := range runes {
-		if c == '<' {
+		if c == '<' || c == '>' {
 			linkEnd = i
 			break
 		}