feat: change publication communication empty message error

[jonat75]

Closes #1804

[github-actions]

🎉 Deployment for commit 59ac733 :

Ingresses

• 🚀 https://egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/
• 🚀 https://egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/api(/|$)(.*)
• 🚀 https://egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/api/auth(/|$)(.*)
• 🚀 https://egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/dgt-export-representation.xlsx
• 🚀 https://egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/dgt-representation.xlsx
• 🚀 https://egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/dgt.xlsx
• 🚀 https://egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/full.ndjson
• 🚀 https://egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/index-egalite-fh.xlsx
• 🚀 https://egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/index-egapro/recherche(/|$)(.*)
• 🚀 https://egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/indexes.csv
• 🚀 https://maildev-egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/
• 🚀 https://pgweb-egapro-feat-publication-communication-message-5g8k17yj.dev.fabrique.social.gouv.fr/

Docker images

• 📦 docker pull ghcr.io/socialgouv/docker/nginx:7.0.1
• 📦 docker pull harbor.fabrique.social.gouv.fr/egapro/egapro/api:sha-59ac7337016707288cb6486717eed05973cefdf8
• 📦 docker pull harbor.fabrique.social.gouv.fr/egapro/egapro/app:sha-59ac7337016707288cb6486717eed05973cefdf8
• 📦 docker pull maildev/maildev:2.1.0
• 📦 docker pull sosedoff/pgweb:0.14.1

Debug

• 📕 Loki logs for namespace egapro-feat-publication-communication-message-5g8k17yj
• 📈 Pods monitoring for namespace egapro-feat-publication-communication-message-5g8k17yj
• 📈 Workloads monitoring for namespace egapro-feat-publication-communication-message-5g8k17yj

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