Update Send button bg color (#5170)

* Update Send button bg color

Change the gradient bg to accent/rest.

* Tidy-up ComposerToolbar to match iOS 18 Figma.

Also simplifies the tests a bit.

* Add a .glassEffect to Compound's SendButton.

* Add a border to TimelineReplyView.

Also use the same sizes in both the message bubbles and the composer.

* Change icon size and container in message bubbles

- Container size = 36x36px
- Icon size = 24x24px

* Update icon of reply contents to be 24x24

* Update the VoiceMessageButton to match the designs.

* Adopt Liquid Glass in the ComposerToolbar.

* Generate and fix snapshots.

---------

Co-authored-by: Doug <douglase@element.io>

compound-ios/Tests/CompoundTests/__Snapshots__/PreviewTests/sendButton.iPad-en-US-0.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:acfb01682b484e788e3fd8f883977baaf488cc7cea84da845fbe0bab8185733d
-size 79822
+oid sha256:9dbba8e66eeb5c78a165952f3dcf2773708178f4d6e4a4a527e69b81b950ceb2
+size 76551

compound-ios/Tests/CompoundTests/__Snapshots__/PreviewTests/sendButton.iPhone-en-US-0.png

@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:8857d2a0cc92634cf7f55390e9fd5a3b23bc496ebc25c2bd4fb660bb191c04d1
-size 39502
+oid sha256:5f972698dc7c7d720205c3ce53426a43b28a638778c1d238341c84fc85542f69
+size 35696