chore:pubsub topic && content_topic encoding is optional

[AYAHASSAN287]

Background

When calling API get /store/v3/messages with pubsubTopic encoded or not encoded it works

[...]

Details

ex :
curl -v -X GET "http://127.0.0.1:49153/store/v3/messages?includeData=true&pubsubTopic=/waku/2/rs/3/0&pageSize=20&ascending=true"

or call it encoded
ex:

curl -v -X GET "http://127.0.0.1:5213/store/v3/messages?includeData=true&pubsubTopic=%2Fwaku%2F2%2Frs%2F3%2F0&pageSize=20&ascending=true"

in both cases it works ang got the message with correct topic name

Acceptance criteria

According to specs pubsubtopic shall be encoded

so behavior and specs Don't match either specs shall mark the encoding as optional or SW change to mandatory

Note: same for content_topic