Improve the user flow to add new bridge lines
## Design estimate
- **Complexity:** large (6 days)
- **Uncertainty:** low (1.1)
- **Total:** 6.6 days
- **Actual:**
## User story
As a Tor Browser user in a heavily censored region
<br>I want to manually add bridges
<br>So I can bypass censorship
## Opportunity statement
As Tor Browser for Android improves and gets closer to its desktop version, we need to make sure the user experience between both platforms is similar and coherent. For that, we should improve the UI of "Add bridges" and "Replace bridges" flows in the Connection settings to make it easier for users who want to manually add bridges on Android - which means the UI for desktop might receive adjustments.
## Scope
- Adjust "Add bridges" flow
- Adjust "Replace bridges" flow
- Improve validation states
## Out of scope
- Lox invites
## References
### Previous designs
[Tor Browser 12.5](https://www.figma.com/design/RS584DcR4emXrw1F8g3l5x/Tor-Browser-12.5?node-id=102-13802&t=bwZFIQ3aHGlOe1q5-1)
### Jag's experimentations


## Mockups on Figma
TBD
## Acceptance criteria
### Scenario 1: Add new bridges
Given the user is accessing the Bridges section at Connection settings<br>
And has no bridges configured<br>
When they click on the "Add new bridges" button<br>
Then a modal appears for them to add bridge lines
### Scenario 2: Replace bridges
Given the user is accessing the Bridges section at Connection settings<br>
And already has bridges configured<br>
When they click on the "Replace bridges" button<br>
Then a modal appears for them to change their bridge lines
### Scenario 3: Invalid bridge lines
Given the user has invalid bridge lines\
And wants to add them in Connection settings\
When they paste the lines in the text input\
And clicks on the "Next" button\
Then an error feedback is displayed
issue