chore(build): only build if image doesn't exist

[ptlc8]

This PR :

• change build actions (docker and depot) to build only if the image doesn't already exist -> faster deploy + faster rerun
• add an input to force build if needed
• use local version of botpress actions
• mask ecr credentials in tag-and-deploy action
• seems to don't implement breaking change

[ptlc8]

working job example: https://github.com/botpress/sso/actions/runs/22146283785/job/64024679720