Make System prompt input area bigger to show the place holder text

[srirambv]

Description

Make System prompt input area bigger to show the place holder text

Steps to reproduce

1. Open Leo settings
2. Click on Add model
3. Scroll down to System prompt
4. Input filed has a wall of placeholder text and is not easy to read it when you need to scroll down

Actual result

Expected result

maybe something like

Reproduces how often

Easily reproduced

Brave version (brave://version info)

Brave	1.74.15 Chromium: 131.0.6778.85 (Official Build) beta (64-bit)
Revision	d1293587128488865fa61e9fa277dd54aa2270b0
OS	Windows 11 Version 23H2 (Build 22631.4460)

Channel information

• [ ] release (stable)
• [x] beta
• [x] nightly

Reproducibility

• [ ] with Brave Shields disabled
• [ ] with Brave Rewards disabled
• [ ] in the latest version of Chrome

Miscellaneous information

cc: @jonathansampson @mattmcalister

[aguscruiz]

Additionally, @jonathansampson would it be possible to change the text fields/areas to Nala components?

https://nala.bravesoftware.com/?path=/docs/components-input--docs

[jonathansampson]

Additionally, @jonathansampson would it be possible to change the text fields/areas to Nala components?

https://nala.bravesoftware.com/?path=/docs/components-input--docs

Definitely can give that a look. Should it be merged with this issue, or split off into its own?

[aguscruiz]

Up to you, I'm fine either way. Thank you!

[jonathansampson]

@aguscruiz Just submitted https://github.com/brave/leo/pull/924 to introduce support for multiline/textarea components. If that can land, it will open us up to using it in this context.