core/mnemonic: cancel homescreen before seed progress animation

If we close the default layout before the animation starts, the workflow manager starts it again after the current workflow ends (and no layout is running).

core/src/apps/common/mnemonic/__init__.py

@@ -1,13 +1,12 @@
 from micropython import const
 
-from trezor import ui, wire
+from trezor import ui, wire, workflow
 from trezor.crypto.hashlib import sha256
 from trezor.messages.Success import Success
 from trezor.utils import consteq
 
-from . import bip39, slip39
-
 from apps.common import storage
+from apps.common.mnemonic import bip39, slip39
 
 TYPE_BIP39 = const(0)
 TYPE_SLIP39 = const(1)
@@ -46,6 +45,7 @@ def module_from_words_count(count: int):
 
 
 def _start_progress():
+    workflow.closedefault()
     ui.backlight_fade(ui.BACKLIGHT_DIM)
     ui.display.clear()
     ui.header("Please wait")
@@ -57,3 +57,7 @@ def _render_progress(progress: int, total: int):
     p = 1000 * progress // total
     ui.display.loader(p, False, 18, ui.WHITE, ui.BG)
     ui.display.refresh()
+
+
+def _stop_progress():
+    pass

core/src/apps/common/mnemonic/bip39.py

@@ -29,7 +29,9 @@ def store(secret: bytes, needs_backup: bool, no_backup: bool):
 
 def get_seed(secret: bytes, passphrase: str):
     mnemonic._start_progress()
-    return bip39.seed(secret.decode(), passphrase, mnemonic._render_progress)
+    seed = bip39.seed(secret.decode(), passphrase, mnemonic._render_progress)
+    mnemonic._stop_progress()
+    return seed
 
 
 def check(secret: bytes):

core/src/apps/common/mnemonic/slip39.py

@@ -82,6 +82,8 @@ def get_seed(encrypted_master_secret: bytes, passphrase: str):
     mnemonic._start_progress()
     identifier = storage.get_slip39_identifier()
     iteration_exponent = storage.get_slip39_iteration_exponent()
-    return slip39.decrypt(
+    master_secret = slip39.decrypt(
         identifier, iteration_exponent, encrypted_master_secret, passphrase
     )
+    mnemonic._stop_progress()
+    return master_secret