[BUG] [Workspace] workspace name missing validation on blank input

[Hailong-am]

Describe the bug

when we create a new workspace, the validation rule for workspace name is to check it don't have special character and only allow a-z, A-Z, 0-9, (), [], _ (underscore), - (hyphen) and (space).

OpenSearch-Dashboards/src/plugins/workspace/public/components/workspace_form/utils.ts

Lines 39 to 46 in d2e7b9d

	export const isValidFormTextInput = (input?: string) => {
	/**
	* This regular expression is from the workspace form name and description field UI.
	* It only accepts below characters.
	**/
	const regex = /^[0-9a-zA-Z()_\[\]\-\s]+$/;
	return typeof input === 'string' && regex.test(input);
	};

But for blank input as workspace name, it can pass the validation and created successfully.

workspace with blank name will be not clickable on workspace list page and hard to tell what it is in workspace switcher.

To Reproduce
Steps to reproduce the behavior:

1. Go to '...'
2. Click on '....'
3. Scroll down to '....'
4. See error

Expected behavior

workspace name with blank should be blocked for creation and updation

OpenSearch Version
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Dashboards Version
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Plugins

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Screenshots

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Host/Environment (please complete the following information):

• OS: [e.g. iOS]
• Browser and version [e.g. 22]

Additional context

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[ananzh]

@Hailong-am I will remove the untriaged label for now.

[SuZhou-Joe]

#7512