Fix displaying texts in Loading in case of arguments are not passed

[alioguzhan]

Current behavior:

If we omit the loadingPrimary and loadingSecondary props, the component still displays the translation keys (ra.page.loading and ra.message.loading) beneath the spinner.

This fixes that.

[fzaninotto]

Thanks!

[WiXSL]

@alioguzhan we made a mistake here.
Your changes make the component not use the translation function anymore.
Actually, the problem you are trying to solve is the expected behavior.
You need to pass an empty string in loadingPrimary and loadingSecondary in order to not see the default messages

[alioguzhan]

Hmm, I see. I can revert the changes, No problem. But, Isn't it weird that we have to pass empty strings to hide the messages? Maybe we can find another solution? Like passing a flag hidePrimaryMessage and hideSecondaryMessage ? Or an options flag. Examples:

1:

<Loading hidePrimary hideSecondary />

2:

<Loading options={{ hide: { primary: true, secondary: false} }} /> 

We can find an alternative better than:

<Loading loadingPrimary="" loadingSecondary="" />

What do you think? @WiXSL

[WiXSL]

We've already reverted them.
We would like to keep react-admin components as simple as possible.
If the Loading component doesn't fit your needs, and you don't want to show any messages, you can use for example a MUI CircularProgress based component like the Loading component does.

[alioguzhan]

Fair enough. Thanks for your time! @WiXSL