fix(NcFormGroup): decrease gap between label and content

[ShGKme]

☑️ Resolves

• A minor bug
• The gap is 16px
• In the design it was the gap between the text baseline and the content
• In the implementation it is a gap between the text block (including lint-height) and the content

🖼️ Screenshots

🏚️ Before	🏡 After

🏁 Checklist

• ⛑️ Tests are included or are not applicable
• 📘 Component documentation has been extended, updated or is not applicable
• 2️⃣ Backport to stable8 for maintained Vue 2 version or not applicable

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 51.57%. Comparing base (06e167c) to head (a5dce77).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #7775   +/-   ##
=======================================
  Coverage   51.57%   51.57%           
=======================================
  Files          96       96           
  Lines        3143     3143           
  Branches      863      864    +1     
=======================================
  Hits         1621     1621           
  Misses       1274     1274           
  Partials      248      248           

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[ShGKme]

• Resolved the conflict

[ShGKme]

/backport to stable8

[backportbot]

The backport to stable8 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable8
git pull origin stable8

# Create the new backport branch
git checkout -b backport/7775/stable8

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick a5dce77f

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/7775/stable8

Error: Failed to check for changes with origin/stable8: No changes found in backport branch

---

Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.

[ShGKme]

/backport to stable8

[backportbot]

The backport to stable8 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable8
git pull origin stable8

# Create the new backport branch
git checkout -b backport/7775/stable8

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick a5dce77f

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/7775/stable8

Error: Failed to check for changes with origin/stable8: No changes found in backport branch

---

Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.