refactor(finance): simplify maskedNumber implementation

[ST-DDT]

let template = '';

for (let i = 0; i < length; i++) {
  template = `${template}#`;
}

can be reduced to:

let template = '#'.repeat(length);

That in combination with the transformation:

let template = '#'.repeat(length);
...
template = this.faker.helpers.replaceSymbolWithNumber(template);

can be reduced to:

let template = this.faker.string.numeric({ length });

[codecov]

Codecov Report

Merging #2493 (f763eff) into next (fdafaa4) will decrease coverage by 0.01%.
The diff coverage is 100.00%.

Additional details and impacted files

@@            Coverage Diff             @@
##             next    #2493      +/-   ##
==========================================
- Coverage   99.58%   99.58%   -0.01%     
==========================================
  Files        2823     2823              
  Lines      255503   255497       -6     
  Branches     1104     1100       -4     
==========================================
- Hits       254452   254445       -7     
- Misses       1023     1024       +1     
  Partials       28       28              

Files	Coverage Δ
src/modules/finance/index.ts	100.00% <100.00%> (ø)

... and 1 file with indirect coverage changes