Bug #110545 mysql shell does not accept some parameters of defaults file

Description:
Several MySQL utilities can use defaults file, where the user can specify options that they want used by default to connections. Unfortunately, the shell does not seem to like/understand at least some options that other MySQL utilities do. 

Example:
```
[ 8752 ] user@host ~/sandboxes/msb_8_0_27 % ➜  cat my.sandbox.cnf |grep -v '^#.*' |head -n 10

[mysql]
prompt='mysql [\h:8027] {\u} (\d) > '

[client]
user               = msandbox
password           = msandbox
port               = 8027

[ 8754 ] user@host ~/sandboxes/msb_8_0_27 % ➜  mysql --defaults-file=my.sandbox.cnf -e 'select 1'
+---+
| 1 |
+---+
| 1 |
+---+

[ 8755 ] user@host ~/sandboxes/msb_8_0_27 % ➜  mysqlsh --defaults-file=my.sandbox.cnf
While processing defaults options:
mysqlsh: unknown option --default-character-set
```

This means that the same options file cannot currently be used for the shell and other utilities.

How to repeat:
See steps in the example given in the description.

Suggested fix:
If the option specified in the file makes sense, support it and use it. If it does not make sense for the shell, even if it does for other utilities, log a warning specifying that it is ignored instead of failing to start the shell.

I can't reproduce this, there's no default-character-set option in the cnf file that was pasted.

Apologies, the pipe to head was chopping the relevant part. Here it is:

```
[ 8828 ] user@some-host ~/sandboxes/msb_8_0_27 % ➜  cat my.sandbox.cnf |grep -v '^#.*' |head -n 12

[mysql]
prompt='mysql [\h:8027] {\u} (\d) > '

[client]
user               = msandbox
password           = msandbox
port               = 8027
socket             = /var/folders/8p/60l87z5s4v95qxxxp3q59fv00000gp/T/mysql_sandbox8027.sock
default-character-set = utf8mb4
```

Thank you for the bug report. Please try with latest version. Thanks.

It does not yet seem to work, neither with 8.0.35 nor with 8.2.1:

```
user@host ~/sandboxes/msb_8_0_33 % ➜  mysqlsh --version
mysqlsh   Ver 8.0.35 for macos13 on x86_64 - for MySQL 8.0.35 (MySQL Community Server (GPL))

user@host ~/sandboxes/msb_8_0_33 % ➜  mysqlsh --defaults-file=my.sandbox.cnf -sql -e 'select 1'
While processing defaults options:
mysqlsh: unknown option --default-character-set

user@host ~/sandboxes/msb_8_0_33 % ➜  mysqlsh --version
mysqlsh   Ver 8.2.1 for macos13 on x86_64 - for MySQL 8.2.0 (MySQL Community Server (GPL))

user@host ~/sandboxes/msb_8_0_33 % ➜  mysqlsh --defaults-file=my.sandbox.cnf -sql -e 'select 1'
While processing defaults options:
mysqlsh: unknown option --default-character-set
```

Shell 8.3.0 still complains about it. 
Meaning upgrade_checking of 8.0.36 to 8.3.0 is not possible !

ok, it seems that default-character-set is not needed. 
8.0.36 works normally without it.

Hello Eduardo Ortega,

Thank you for the bug report.
Discussed your issue internally with the developer and concluded that this is not a bug. 
Options that are not supported by all clients should either be moved from [client] to [mysql] etc  or prefixed with loose-

Regards,
Ashwini Patil