Standardize textarea styling across forms with compact textarea class

[maxtaube]

Description

Standardizes textarea styling across create/edit forms by switching affected fields to the shared compact textarea treatment.

Changes included:

• adds/uses the shared compact textarea styling in core form styles
• updates the affected textarea fields in Goals and Scheduled Reports
• applies the same compact textarea treatment in CustomReports and FormAnalytics

Checklist

• [✔] I have understood, reviewed, and tested all AI outputs before use
• [✔] All AI instructions respect security, IP, and privacy rules

Review

• Functional review done
• Potential edge cases thought about (behaviour of the code with strange input, with strange internal state or possible interactions with other Matomo subsystems)
• Usability review done (is anything maybe unclear or think about anything that would cause people to reach out to support)
• Security review done
• Wording review done
• Code review done
• Tests were added if useful/possible
• Reviewed for breaking changes
• Developer changelog updated if needed
• New documentation added or existing documentation updated

[AltamashShaikh]

@maxtaube LGTM, can we add a small screenshot which ensures the description auto expands to new line, when the length of description is > width