[Explorer]: add bottom border for tab list (#13307)

## Description 

Describe the changes or additions included in this PR.

## Test Plan 

How did you test the new or updated feature?

---
If your changes are not user-facing and not a breaking change, you can
skip the following section. Otherwise, please indicate what changed, and
then add to the Release Notes section as highlighted during the release
process.

### Type of Change (Check all that apply)

- [ ] protocol change
- [ ] user-visible impact
- [ ] breaking change for a client SDKs
- [ ] breaking change for FNs (FN binary must upgrade)
- [ ] breaking change for validators or node operators (must upgrade
binaries)
- [ ] breaking change for on-chain data layout
- [ ] necessitate either a data wipe or data migration

### Release notes

apps/explorer/src/ui/Tabs.tsx

@@ -39,15 +39,14 @@ const tabStyles = cva(
 		},
 	},
 );
-
 const tabListStyles = cva(['flex items-center border-gray-45'], {
 	variants: {
 		fullWidth: {
 			true: 'flex-1',
 		},
 		disableBottomBorder: {
 			true: '',
-			false: '!border-b',
+			false: 'border-b',
 		},
 		gap: {
 			3: 'gap-3',
@@ -56,6 +55,7 @@ const tabListStyles = cva(['flex items-center border-gray-45'], {
 	},
 	defaultVariants: {
 		gap: 6,
+		disableBottomBorder: false,
 	},
 });