fix(cli): set inputNamePattern to RegExp source instead of string

[rafedramzi]

Goal: set inputNamePattern to RegExp source instead of string so the testNamePattern can be easily reused

Impact: when running the vitest in watch mode with --testNamePattern, when pressing t to re-run the filtered test, the suggested value is wrong and value cannot be reused because it has / /

1. actual filter: role admin
2. 1st t press, it suggest /role admin/
3. 2nd t press, it suggest /\/role admin\//

version: 0.24.3
cause:
using RegExp.toString() returns a valid regex string (with / at the beginning and the end of the string), but when this value is reused as RegExp constructor, it tries to covert the string value in to regex, causing the those / to be escaped.

simplified code to reproduce this issue

// Actual
const reg1: RegExp|undefined = new RegExp("foo");
const reg2 = new RegExp(String(reg1||''));
const reg3 = new RegExp(String(reg2||''));

console.log(reg1, reg2, reg3);


// Expected
const eReg1: RegExp|undefined = new RegExp("bar");
const eReg2 = new RegExp(eReg1?.source||'');
const eReg3 = new RegExp(eReg2?.source||'');
console.log(eReg1, eReg2, eReg3);

output

/foo/ /\/foo\// /\/\/foo\/\//
/bar/ /bar/ /bar/