URLs only count for 23 characters of mastodon post limit - but metatext counts them all

[alexbbrown]

Describe the bug

From the mastodon help:
URLs in text always count for 23 characters

When composing a toot in metatext it displays the toot character limit (eg500) and how many more characters you can add to your post before the limit is exceeded

but when adding a 100 character URL it subtracts 100 characters from the limit, instead of 23

unless the URL is on the first line

To Reproduce
Steps to reproduce the behavior:

1. open metatext
2. Tap compose
3. Observe limit 500 remaining
4. Enter this URL

 https://www.researchgate.net/profile/Marc-Smith-12/publication/215643659/figure/fig2/AS:305995675914242@1449966462078/Microsoft-Outlook-Expresss-newsgroup-browsing-interface.png

5. Observe remaining limit is 477
6. Add one carriage return at the start of the toot
7. Observe remaining limit is 322

Expected behavior
subtract 23, regardless of the length of the URL

Screenshots
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(please complete the following information):

• Device: iPhone 12
• OS: iOS 16.2
• App Version : 1.7

Additional context
Add any other context about the problem here.