Fix reaction of issues (#21185)

[wolfogre]

Backport #21185.

Fix #20860.

CommentID in FindReactionsOptions should be -1 to search reactions with zero comment id.

gitea/models/issues/reaction.go

Lines 108 to 121 in 8351172

	func (opts *FindReactionsOptions) toConds() builder.Cond {
	// If Issue ID is set add to Query
	cond := builder.NewCond()
	if opts.IssueID > 0 {
	cond = cond.And(builder.Eq{"reaction.issue_id": opts.IssueID})
	}
	// If CommentID is > 0 add to Query
	// If it is 0 Query ignore CommentID to select
	// If it is -1 it explicit search of Issue Reactions where CommentID = 0
	if opts.CommentID > 0 {
	cond = cond.And(builder.Eq{"reaction.comment_id": opts.CommentID})
	} else if opts.CommentID == -1 {
	cond = cond.And(builder.Eq{"reaction.comment_id": 0})
	}