fix: error when navigating to a post that has no tags
fix: error when navigating to a post that has no tags

hb-gatsby/gatsby-starter-lumen,alxshelepenok/gatsby-starter-lumen,nicklanasa/nicklanasa.github.io,renegens/blog,wpioneer/gatsby-starter-lumen,ochaloup/blog.chalda.cz,alxshelepenok/gatsby-starter-lumen,nicklanasa/nicklanasa.github.io,renegens/blog,ochaloup/blog.chalda.cz