Update plan.js

[Phpvarious]

1. Change ccs of old version of jeedom (now is flex)
2. Reset update function during a displayplan()

Suggested changelog entry

1. Correction d’un bug de centrage vertical sur le design lorsque le titre est masqué.
2. Réinitialisation des fonctions d'update avant l'affichage d'un design.

Related issues/external references

1. https://community.jeedom.com/t/widget-plus-centre-une-fois-le-nom-masque/125032
2. https://community.jeedom.com/t/widget-distribution-onduleurs/125074/6?u=phpvarious

Types of changes

• Bug fix (non-breaking change which fixes)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)
  • This change is only breaking for integrators, not for external standards or end-users.
• Documentation improvement

PR checklist

• I have checked there is no other PR open for the same change.
• I have read the [La ligne directrice pour contribuer à ce projet / Contribution guidelines for this project).
• I grant the project the right to include and distribute the code under the GNU.
• I have added tests to cover my changes.
• I have verified that the code complies with the projects coding standards.
• [Required for new sniffs] I have added MD documentation for the sniff.