Fix/ Flash message display logic

[ghassenbenzahra123]

📝 Summary

This PR fixes #1036 & #972

Description

Fix flash message display logic to handle all cases for start & end date.

Tests

🧪 Use case 1

💬 Description:

Only Startdate selected the flash message should display starting that date until the user cancel it .

🧪 Use case 2

💬 Description:

Only Enddate selected the flash message should display immediately until passing the endDate .

🧪 Use case 3

💬 Description:

Both start & end date selected the flash message should display between the selected values.

🧪 Use case 4

💬 Description:

Neither start or end date is selected the flash message should always display until the user cancel it.

Checklist:

• [x] Coding Standards: I have reviewed my code to ensure it follows the project's coding standards.
• [x] Testing: I have tested the changes and they work as expected.
• [x] Merge Conflicts: I have resolved any merge conflicts with the latest main/development branch.
• [x] Branch Status: The branch is up-to-date with the target branch (main/development).