Completing the most urgent context-specific task shows nag

When I complete the most urgent task within a context, but there is a more urgent task outside of the context, I will still show the nag aka "You have more urgent tasks."

## What command(s) did you run?

Relevant `.taskrc`
```
context.dava.read=+dava
```

To reproduce with empty data dir
```
task context none
task add Urgent task outside context due:now
task add Most urgent task inside context +dava
task list
task context dava
task list
task done 2
```

Output:

## What did you expect to happen?

I expected to not be shown the message "You have more urgent tasks.", since I completed the most urgent task within the given context.

`task diag`:
```
task 2.6.2
Platform: Darwin

Compiler
Version: Apple LLVM 14.0.0 (clang-1400.0.29.202)
Caps: +stdc +stdc_hosted +LP64 +c8 +i32 +l64 +vp64 +time_t64
Compliance: C++17

Build Features
CMake: 3.25.1
libuuid: libuuid + uuid_unparse_lower
libgnutls: 3.7.8
Build type: Release

Configuration
File: /Users/jneidel/.config/task/taskrc (found), 906 bytes, mode 100644
Data: /Users/jneidel/tmp/.task (found), dir, mode 40755
TASKDATA: /Users/jneidel/tmp/.task
Locking: Enabled
GC: Enabled
$EDITOR: vim
Server:
CA: -
Certificate: -
Key: -
Trust: strict
Ciphers: NORMAL
Creds:

Hooks
System: Enabled
Location: /Users/jneidel/.config/task/hooks
(-none-)

Tests
Terminal: 120x30
Dups: Scanned 3 tasks for duplicate UUIDs:
No duplicates found
Broken ref: Scanned 3 tasks for broken references:
No broken references found
```