Rive Text for iOS and Android!

Adding rive text support to ios.

@mjtalbot Sorry for the shell script format churn, this is my formatter in case we want to standardize on one:
https://github.com/foxundermoon/vs-shell-format
```
  "[shellscript]": {
    "editor.defaultFormatter": "foxundermoon.shell-format"
  },
```

Also, I couldn't test the MacOSX build thoroughly as I was getting a Metal error on run which wasn't related to the text changes. But maybe I'm running the wrong project (this is the iOS one which I thought we were sharing)? Not sure which one I should run for Mac. This is the error:
<img width="847" alt="CleanShot 2023-07-20 at 16 29 56@2x" src="https://github.com/rive-app/rive/assets/454182/6c2f70f9-c8f4-4b50-a3cb-753a861e2e0b">

Diffs=
13863bf8f Rive Text for iOS and Android! (#5634)

.rive_head

diff --git a/.rive_head b/.rive_head
index 20aa516..41811a2 100644
--- a/.rive_head
+++ b/.rive_head
@@ -1 +1 @@
-9e0c43b70a4f25342bf4572d1284c01b4781cf99
+13863bf8f83c360422e9b8e924660a57e902b524

submodules/rive-cpp

diff --git a/submodules/rive-cpp b/submodules/rive-cpp
index 9b93265..f47bd6a 160000
--- a/submodules/rive-cpp
+++ b/submodules/rive-cpp
@@ -1 +1 @@
-Subproject commit 9b9326566eb966d13e1b6b289aef2dcf2ac33b2e
+Subproject commit f47bd6a5d2abd448f005747138164ccf0be2f447